I have been playing Street fighter 4 for about 3 months now and I know all of the basics but I have no idea WHEN I should use certain moves like any move or normal attack, I have no idea what would be the best time to use them so I usually just do random moves/normals when it is safe to keep the opponent guessing but it just doesn't work, I know I should use combos and chains so I learnt one for rolento but I still don't know when I should use it, I get you need to punish people but they are never in the position to get punished because they never make the first move. I also tried picking a main character to use, first I picked Blanka who was fun to play but I was told he was way too easy to punish and beat and I just couldn't play him that well so I changed to Rolento who I like a lot but I'm still having the same problem of not knowing when to do certain things. So when I try to practice in endless with random people, after one round they get annoyed at how bad I am and kick me from the lobby so it's even harder to practice. Could anyone explain what I should do? Thanks.

EDIT: I am NOT new to the game, I have been playing almost every day for a while now, I understand almost all the basic-intermediate mechanics.