Advise on 2 for Slytherins: Forgotten recommendations are an opportunity. People generally won't think of you as an acquaintance until they've interacted with you a few times. Recommendations provide excuses to get in contact with people for a second or third time (for clarification or thanks) while flattering their judgement. I have heard of people pretending to forget recommendations just so they can contact someone to ask about it*.

There's a saying about courting donors: "If you want advice, ask for money. If you want money, ask for advice."

*I am a Hufflepuff and do not condone such action