it's my understanding that buff is one of the most complicated colors to begin with, try and breed around. It's quite commonly detered away from- mainly from the point of complexity.
You can't get something, from nothing- unless it's hidden recessive... Meaning if you're breeding buffs to buff.. You're not going to get blues. Now, your buffs could likely carry black or white-- that'd be your best option for getting any other color from them.
if you want to make your own color- you're going to expand your color knowledge by about thousand fold-- especially since you know almost nothing; hence you asking this question. You can make your own 'new' colors by injecting and improving upon your breed of choice- but through this process you're going to need to know alot, have plenty of time to get where you want to go- and be able to ruthlessly cull thousands of birds over the years.
The quickest, easist way for you to be able to have the colors you desire-- is purchase them from somebody who's already done that, and is producing them on a consistant basis- even though some colors won't breed on true. With this in mind, more than likely the cheapest, easiest, best option is start over fresh from scratch.