First thing about baking a scratch cake is, don't freak out, it is not as scary as it seems!
With cooking "a little of this and a little of that" works well. However, in baking, it is important to measure your ingredients carefully. Fill a measuring cup with flour, don't shake or tap it, and run a straight edge over the top. If it says to sift, or to mix dry ingredients in a separate bowl, do it.
Just relax, and have fun with it. Start with a very basic recipe first - I would actually suggest doing a chocolate cake first rather than a white one.
If you need recipes, just check out the cakes forum here! There are many TNT ones to choose from.
"Variety is not just the spice of life, it is the key to life" - Chef Michael Smith