We planted a lot of basil (way too much) close together this year, with
the intent of thinning them once they got going. Well, fast-forward to
today, and we never really got around to that thinning until this week,
so the plants aren't doing as well as they should.

My question:

Is there anything in particular I could/should be doing for them to
give them a boost now that their living conditions have improved? I
feed the plants diluted fish fertilizer, water regularly, and they're
in bright sun most of the day. Just wondering if there's anything basil
likes with which I could help it realize its potential.