I find if you grab your guitar every day it will help, even 5 mins a day is good, I think I average 15-30mins a day. You just need to have an idea on what you want to work on or what you want to do on it. Also, for some peculiar reason, sometimes I’ve found I can’t work out how to do something the first day I try it, even if I can’t get it successfully done once, I’ll come back the next day and I can do it.
Probably a second good bit of advice I found was from Robert Baker who said to make sure you end on a good note. So even if your practice isn’t going at all well for whatever you’re trying to learn, make sure you finish on a song or riff you can do and is fun — that way you don’t do the whole ‘ugh.. couldn’t work that thing out.. won’t bother trying today’