Good session, Himu. You wanted some advice, and this is what I noticed:
-Work on your defense game. You should definitely spend some time getting familiar with how focus attacks work and work on blocking high and low.
-When you're up against a grappler like Zangief and using a smaller/faster character, RUN!!
Play keep-away. Zone the fuck out the opponent with projectiles. If Gief gets in close, that SPD has a vacuum effect and is going to grab you from a little further away than it might seem. Don't try to do anything too complex up close; just punish and keep the grapplers out with well-placed normal attacks. A lot of the dumber players can't beat Chun's jump straight up and HK. You can do it all day and they're fucked.
-Speaking of pokes..poke! It will take some learning/research but you'll find the best pokes to help get more complex stuff started.
-Street Fighter really isn't a combo-heavy game. It's more about fundamentals/spacing/pokes/footsies/etc. Don't worry too much about crazy combos and work on the basics first.
-I would recommend learning one or two combos/strategies at a time and then work on getting them off in various situations online. It doesn't help if you memorize something but then can't actually get it to hit your opponent. I encounter players like this far too often...too much time spent "in the lab" and not enough time actually playing people.
-Keep trying different characters. You never know who you'll end up liking.
-If the charge characters aren't making sense to you, there's nothing wrong with just dropping them and using fb/dp characters instead. Could be that charge moves just don't suit you. I know that Justin Wong will not play Chun-Li in any game where her fireball is a charge because he hates that input for her projectiles.
I think you did the best with Ryu, but that could easily transfer over to Poison. The best Poison players I've seen do a lot of zoning when far away (her projectiles are awesome; remember that the lp version goes the farthest) and then base a lot of her close-up game around her "whip rekkas" (the multi-hit qcb+p x3 movie)off of pokes. You can easily hit it off of crouching MK, for example.
But it's pretty much just all about playing so you get familiar with characters and match-ups.