Welcome to the Platinum boards! I'd say the best way to learn how to deal with certain situations is by recreating them in Training Mode. Trying to find punishable gaps in blockstrings, and etc. and if you want to learn about lingo and terminology you should go to the beginner's section of Dustloop http://www.dustloop.com/forums/forumdisplay.php?100-Beginner-Mode here is the link. If you have any more questions, ask here or in the Q&A topic and don't be afraid to ask people for help, most of us are usually nice here. Enjoy your stay!
We all know what you mean. Most Plat videos I see are mainly of her losing pretty badly to either top-tiers or because of horrible luck. Platinum is very unorthodox as a Blazblue character. You have to make your own luck with using her. Make the best out of a bad situation, never think about giving up. The moment you do, You already lost the match. Any character can be viable in High Level Play (Dora uses Bang and he did extremely well in SBO and Spark won EVO using Hakumen) just have to work hard at it and Plat has enough tools to make it happen. Till this day I still have problems with Rachel,Litchi,Hazama,Jin and Lambda as Plat but I try my hardest to win with what I have because of the love I have for my character. (lol I know it sounds corny and kinda wrong but hey Platinum is a cool character and I wouldn't drop her for anyone else in BB.)
tl;dr:
Try being annoying with her.
Some characters actually tech out early if you do J.B J.C djc J.D. :/ ggs proration.
EDIT: nvm, I was thinking of j.B J.C J.B J.D, but by all means go for whatever's easier.