Jamie is right... the search function on this site is not very user-friendly. I use Google advanced search too... it's right next to where you type in what you are searching for.
Technique is everything with scratch baking. Making sure you cream the butter and sugar well (unless you are doing the whole reverse creaming thing from the Cake Bible) and mix in the eggs enough and not over-mix when you are adding the dry ingredients. A good thing to do is weigh your ingredients rather than scoop and measure. This will assure that you get the same exact amount each time. It's also easier... you just scoop until the thing says it's the right weight... LOL. Sifting your dry ingredients is important too as is making sure that your leaveners (be it baking sodaor baking powder) are fresh. Room temp ingredients are a must too... everything just mixes easier so you can avoid over mixing. With mixes you have to mi it for the 2 minutes (or whatever time they say) to activate all the stuff that is dehydrated in them... with scratch baking mixing too long is detrimental. You Tube is a great place to see the techniques in action.
Chocolate cake is easier to master than vanilla. For a really good chocolate cake try this recipe... http://www.epicurious.com/recipes/food/views/Double-Chocolate-Layer-Cake-101275
. It's *really* good and eventhough it sounds like a pain in the ass... it is not really that complicated and the result is worth it!
Some people love the recipe on the Hershey's cocoa can, but I prefer to use different cocoa.
I tend to bake at 325 or less... I have a regular old oven... no convection or anything. If you have a convection oven you should lower it more.