Andy Loomis is the man. If you're considering cartooning he's quite undoubtedly the man to look into.
I haven't had enough time to get back into drawing but I plan to let loose some Loomis in the near future
fnurr, fnurr
In all seriousness, I have to really stress this - even if you want to eventually go for a more cartoony style, DEFINITELY DEFINITELY do some 'real' drawings. Observational stuff of people, animals, objects, the whole shebang. Obviously you don't have to do that exclusively but it's really important to develop your accuracy and skill the 'proper' way even if you end up stylising. Learn the rules before you break them and all that.
Also, look up other artists. Lots of them. Preferably professional / established ones vs. stuff on DA or Sheezy or whatever. Don't just go "HURP DURR I'M GONNA DRAW LIKE DON BLUTH", but go nuts producing studies and looking at how they do what they do.
Lastly, talk to other artists. Exchange tips and read tutorials and basically amass as much information as you concievably can. Continue to do this
forever.
I'm completely serious. Never ever stop learning.