Are all crimes that I commit supposed to fail almost everytime? If not, is there a way I can become more sucessful with them?

Train your speed,and keep stamina on 100%

And read Game Wiki!

Also, theres a crime guide which I found to be pretty useful

Crime guide:  http://www.prisonblock.com/forums/Crime-Guide-t305.html

After so many days of joining, reaching pretty high speed yet i never had any success, other then janitor closet.. i kind of given up from doing crimes...

I even used crime guide nothing worked for me...

after level 5 at new jersey and youcan only raid the janitors closet?  Keep trainig your speed...make sure you have enough Nerve...(NRV) and that your stamina is at 100% like these guys said. Just keep training, you'll get there

it's not easy to run away from police

you don't know about my speed if i use the guide i can do all NY crimes twice in one attempt, but i guess police watch me more then anyone else, may be coz of my status, so couldn't do crimes!!

i'm level two and I am still only sucessful at the janitor's closet crime. Is this normal, or should I b able to do more by now?

http://wiki.prisonblock.com/Crimes

http://www.prisonblock.com/forums/Crime-Guide-t305.html

Crimes are somewhat random, that's what I think anyway. This crime guide is pretty useful to a certain extent, not 100% accurate, it will give you a fair estimate of what your speed should be for each crime.

Also, if you're looking for a 100% success rate, it's not going to happen.