Okay; increasing IQ is, where possible at all, very difficult.
What other, perhaps more specific, cognitive skills with practical value could we try to enhance? A lot of debiasing techniques discussed before fall in this category, but in very narrow ranges of application.
Other cognitive skills are more general-purpose. For instance, are there any known, tested means of improving recall from long-term memory, or improving cognitive focus?
If improving general intelligence is difficult, let's go for any low-hanging fruit first.
Regarding recall from long-term memory: Write it down!
I know a person who actually does that. That recall and precision is greatly improved should be obvious. The problem lies more in acquiring the habit of actually writing everything down if it looks important.
I envision to build something electronic for me, because I hate handwriting. Also that would add search capability.
Transhumanists have high hopes for enhancing human cognitive abilities in the future. But what realistic steps can we take to enhance them now? On the one hand Flynn effect suggests IQ (which is a major factor in human cognition) can be increased a lot with current technology, on the other hand review of existing drugs seems rather pessimistic - they seem to have minor positive effect on low performers, and very little effect on high performers, what means they're mostly of therapeutic not enhancing use.
So, fellow rationalists, how can we enhance our cognition now? Solid research especially welcome, but consistent anecdotal evidence is also welcome.