Situational training online is VERY important. Mainly because it teaches you to be patient and look for oppertunities to open up your opponent. In other words, how to play safe. Trying to punish every little thing will drive you crazy.
its important to take your time and observe your opponent. Watch their tendencies. Do they jump in a lot? Do they drop combos? Do they like to walk up throw?
Do your best to look for things that you know your character can exploit for damage. When you get those oppertunities, punish as HARD as you possibly can then see how they react. Do they try the same thing again? Do they get scared and try and mix it up?
More often than not, If you can scare your opponent away from their game plan with consistent harsh punishment, then you force them to try something uncomfortable and risky. This just gives you more opportunities to punish mistakes.
You can really separate the good from the not so good because the players worth their salt will be able to adapt to what youre doing alot better than those who are not so good.
As you begin to really read and observe your opponent, You will find things become a lot easier because you will know when you have opportunities to really maximize damage. Once you begin to take advantage of that, it takes a lot of pressure off of you.
I hope this helps. Ive been right where you were not long ago. Just be observant, and keep at it.