For "how should I build this", as opposed to "why isn't it working?", writing documentation helps.

For personal projects, typing up an email to the appropriate google group, explaining the problem and requesting help, helps me solve a problem about 50% of the time.

For work projects, verbal diarrhea into Slack is very effective but interrupts colleagues too much (though it does have the side effect of pulling in help on the occasions you really need it). I've been considering building a bot for that.