I (Kat) use Photoshop CS4. I don’t know about Margherita, but I’m she uses Photoshop as well! :) As for tips:

• Try not to use the same coloring (if you do use one on caps) over and over again. It will get boring after some time.  
• It’s always good to tag your confessions so people actually see them. (e.g. “Glee”, “Rachel Berry”, etc.) 
• I recommend not to post confessions like “I hate ____, they just suck.” It will upset people. 

I’m sorry I don’t have many tips, but I hope this is helpful anyways! Have fun and good luck with your blog :)