I'm going to be starting college in the fall, so that obviously gives me a new environment with lots of girls...

The more incentive to develop the skills before the college. You are right that if you approach ten girls every night in the same environment, sooner or later someone will notice. I would suggest training your skills somewhere else, and use the interaction in college only to maintain the level you already have. -- For example if you are uncomfortable making eye contact, train it somewhere else, but when you become comfortable with it, do it every day at the college to strenghten the habit. -- If you change your college behavior slowly and without obvious effort, people won't notice. It will be just "growing up".

Not to mention that I can't just magically make myself not feel shame.

I recommend two powerful branches of modern magic, called "reductionism" and "conditioning". The first one can literally crush mountains to sand, the second one can be used by a wizard to transform themselves. The most successful school of these branches is CBT.

What exactly makes you feel shame? What words do you hear or what video do you see in your mind when you consider talking to an attractive girl? First step, write it down, in as much detail as you can (not publicly). For example: "If I say 'hello' to a girl, she will run away screaming / start laughing at me / coldly ignore me / call the cops." (Merely writing it down helps to dispell the magic, because you notice how silly it is.) Second step, try to trace when and how did this idea get into your mind, and what evidence do you have about its literal truth. Was it said or suggested to you by someone when you were 10 years old? What is the probability that the person (a) had a correct model of the world, (b) had a motivation at given moment to give you a literally correct information, and (c) you understood and remembered it perfectly? Or it is something that happened to you in the past? Are there some specific things about (a) you, (b) the person you are going to interact with, (c) the environment, that have changed? Third step, make a statistics: Take a notebook, make a specific prediction, do the experiment, note the results. Out of 10 approaches, what happened how often?

If something is difficult, try splitting it into smaller pieces, and train it piece by piece. Asking "what time is it now?" is easier and shorter than having a conversation. Making eye contact and smiling for half a second is even easier. But perhaps smiling at a photograph or an imaginary person could be even easier. Even the smile, or more precisely the causal chain in your brain that naturally makes you smile, can be analyzed. Is there a pleasant thought that is likely to make you smile? (Imagine lying at the beach, observing the wide sky under the warm sun.) Try smiling alone, perhaps lying relaxed on your bed, until you feel pleasant doing it. Then smile at photographs, at real people not looking at you, at real people looking at you, starting with the people you know. (Note: If someone asks you why you smile, just say: "I just have a great day" and stop there.) For a successully completed task, reward yourself with an M&M.

Creepiness is a really hard concept to deal with. ... PUA-y stuff saying "men being passionate and clear about their intentions is attractive" ... poorly socially calibrated might do something creepy like writing someone in his class he's talked to a few times a long Facebook message confessing his feelings for her

I think the essence of creepiness is the victim's (real or perceived) inability to easily stop the interaction. The PUA attitude is like: "girl, if you want, my bed is over there and I don't have any mental problem about doing it like rabbits... but if you don't want, I am perfectly okay with that, too; there are other girls who will be happy to get this offer, and meanwhile, we can talk, but we also don't have to". Of course not using those words; this is just the internal model of the world. Clear about: yes, I am a healthy human male. Clear about: you are given the opportunity, but the choice is yours.

On the other hand "confessing feelings" is probably kind of creepy at almost every context. It works only if the girl is at the given moment 100% sure she wants you (and you are so biased to overestimate this), or if you are a fictional Hollywood hero and her positive response is in the script. Rule of thumb: Don't do it, except if the girl does it first, and even then don't make it stronger than she did. Otherwise it can go like: "Oh, this guy needs me so much, but I am not completely sure about him... and maybe I will later decide I don't want him... and maybe then he will do something creepy... so perhaps I should play it safe and get rid of him before he gets even more attached." Not having an easy opportunity to leave, if you decide to, is also creepy. -- Also, if you make a social mistake, leaving a written proof makes it much worse.

There are some PUA techniques to reduce creepiness, for example by introducing an artificial limit like: "Hi -- oh, I am so sorry I must leave within a minute to catch my train -- but I just noticed you and really wanted to say hello." Properly done, the girl now feels no pressure (unless something else is wrong). Of course, you should then leave as promised. (Advanced version: Or have a very credible excuse.) Also, you can send similar signals with your body language; don't lean towards the girl, don't even turn your body against her, only your head. She must feel free to leave; and if she does, you must accept it calmly, preferably with a smile. To keep your mind in the proper state, relax and congratulate yourself for starting the conversation. And eat an M&M. And remember that if she left without any obstacles, she is more likely to talk with you again, perhaps for a longer time.

Note: Feel free to punch me if I talk about dancing lessons too much, but it is a social activity where it is socially okay and even required to touch girls. ;) The idea is to become comfortable with non-zero contact. Actually, for really good ballroom dancing, rather intimate contact is required; but let the girl decide how much is okay for her. It will still be more than zero. To avoid creepiness, make it obvious you expect only one dance at a time from the girl. Then lead her back to her chair, smile, compliment her dancing, and say: thank you. (Rule of thumb: Don't make her send you away or escape from you; leave first.)

I am sure that there are socially acceptable ways to show a girl your attraction that would 80% of the time end up with you not being given the creepy label, regardless of whether or not she reciprocates.

She does something interesting. You approach her (don't go directly to her, just around her), make eye contact, smile, compliment her on what she did, and leave immediately (if possible, don't go back, continue in approximately the same direction). Repeat 20 times (with different girls, in different situations).

"creepy" is also one of the most common critiques people give of PUA

Selection bias: If a PUA does something wrong, people think: "This was a creepy PUA". If a PUA does something right, people think: "This was a charming young man." Attribution error: If you attend a seminar, then smile at a strange girl and say hello, your friends will think: "He never did this before, but after the seminar he keeps smiling at strange girls and saying hello, that's creepy." Everyone else will think: "He is a nice and happy guy." Confirmation bias: If someone has already decided that you are creepy, anything you do will seem creepy to them. -- Therefore, if you learn and use PUA stuff, don't say it to people around you, because then you will get feedback about their models of PUA, not about what you do. (In the worst case they could start punishing all your social behavior. Like, you would do something nice and social that you would have done before too, and they would say: please stop doing this PUA stuff all the time, it's creepy.)

A thought experiment: Imagine than in another universe I would write here on LW exactly the same information and advice, but I would start with the following disclaimer: -- "Please don't ever do PUA. PUA is creepy and it is for losers. It is evil and should be illegal. How about just naturally being yourself, being nice and polite and attractive? Why are guys so opposed to doing that? Are they afraid that they would lose their masculinity? No, that is a patriachal nonsense. Actually, here is some advice from my feminist friends about how to become a real man: ..." -- and then I would follow with all the PUA advice, just being very careful not to ever mention "PUA" or any PUA slang (e.g. "alpha" and "beta"), and to always frame it like: This is how you become a good man (connotationally: good doggie) and make women happier (because that is the only thing that truly matters). Would such version be more socially acceptable? Oh, it certainly would; it would show everyone that I am a good Blue, not an evil Green. So why don't I do it? Well, I am stubborn; and I consider it intellectually dishonest to use someone's knowledge without giving them the proper credit. I am not saying PUAs invented this all, but they certainly widely popularized it. They are the ones who tried to help the low-status male, before it became profitable. I have no problem with using other sources of information on the same topic, as long as the information is useful; I just didn't find any.