Welcome Ohm
When you get a few more posts in, you can start asking more specific questions in the DIY section. I've been mixing for about 5-6 months now. It's awesome. My very first batch of flavors was a 10-pack of LorAnn that I ordered from Amazon (which actually have been quite good for me.... The blueberry and the NY Cheesecake were my favorites!) However, now, I'm leaning more toward The Flavor Apprentice (TFA) and I have been getting those from Wizard Labs.
Susan gave you some great links (as always, thank you dear!) Read the blogs by Hoosier, Dannyv45, and Bill's Magic Vapor for some amazing tips and tricks. Bill's very generous with his recipes, but he tends to use mostly TFA flavorings. Make note, a blueberry, for example, from TFA is going to be slightly different than from LorAnn, which will be different from Capella (CAP) which will be different from Flavor West (FW), etc. And, the percentages that are recommended are merely starting points for the specific flavorings. You may want higher or lower based on your personal preferences.
Start with small batches and realize that some flavors need complements in order to really shine. You don't necessarily know that the secondary flavoring is there, but it could very well be needed in order to enhance the primary flavor.
DON'T GIVE UP! It may be frustrating at first, but you'll eventually get the hang of it, and it will open a whole new world for you!