First of all, I love your avatar. For obvious reason.
Second of all, glad to help. It would really be beneficial if you could post a gameplay video up -- that way, we could all really critique your gameplay. That being said, going with what you posted --
- Basic, solid Ivy is less big damage, more poking. Ivy can be played EXTREMELY safe. Moves like 3K, 6B8K, BB, 2A and 4B are quick and really hard to punish. Her less safe, but still relatively safe options are 22B, A+BA and 2A+B. Use these moves in addition to throws to start opening up your opponent. You'll know when you've done this if the opponent starts ducking.
- Once you have them ducking, abuse 22_88B BE, 1B BE, 3B, 2A+B, B+K and other really strong mids that lead to 70 damage or greater.
- Defensively, don't be afraid to use 214B at disadvantage. You said that you had problems with people locking you in -- using 214B and 7B as 'panic' commands (to use when all else is failing) is a good first step to train yourself in using Ivy. Over time, you'll become more methodical about this, but its good to start getting acquainted with maximizing the advantages of these escape moves while minimizing the cons (bad block frames).
- Lastly, throw. Whether CS, SS or normal throw, Ivy has one of the best grab ranges in the game. Use and abuse it. Use it in different situations to mix up your offense -- for instance, throw is a surprisingly good tool for her wakeup game.
Hope that helps.