Typically I only have one or two books waiting TBR, however, sometimes things to pile up. In this case I not only had a bunch of pre-orders release at the same time but I also found some good deal on ebay on books I'd been looking for for a while now. When things do start to pile up I also stop buying books (unless it's a good deal and I'll definitely read them later). I also read them first in, first out, unless they need to be read in a specific order.
I tend to read a mix of graphic novels and regular novels so I usually have one of each going at a time. My reward for finishing though is getting to read the next book or, if my TBR is empty, buying more books. :)
Recently started a book series referred to as the Murderbot Diaries where the protagonist is essentially a cyborg that hates humans, is socially awkward, and just wants to be left alone to watch media and I've never related to a character so hard!