First, before i answer any of your questions, dont call yourself an "aspiring" cartoonist. Just get rid of that nasty word and start thinking of yourself as a cartoonist or else you wont give yourself the respect and discipline to get things done and have confidence and what not.
!.) are you asking about style or writing? if writing, check this article out, it might help:
enter link description here
if art, then...i dont...actually know what to say...just study the crap out of other people drawings....
2.) This is actually a weird topic that ive seen discussed on this site a lot, and i dont really know if there is a specific answer for this. For one, dont go running to people asking for their subscription, no body likes that. Instead, be friendly and talk to people on the site. The tapastic community is shockingly nice and youll be suprised how interested people are in reading each others stuff. Do guest comics when you can. I see a lot of people create comics for eachother and its really cool.
I will say this, be careful as you enter in the comedy buiseness because comedy and slice of life are the two main comics on Tapastic. A lot of people will be doing excactly what you are doing, so just be mindful of that as you check in on your subscriber count.
Also, dont worry. Things like this take time and effort, so just be patient and have fun!