There are not that many tricks when choosing quickdraws. What we can definitely say is what not to buy. To us there is no sense to get quickdraws with short 10cm or less and rigid slings as on longer routes they will create quite a drag and they are not that resistant to the potential danger when back clipping. Also unless you will aim for long mountain routes where the weight matters a lot we do not recommend you buy super light quickdraws where the carabiners are super small. It is a pain in the ass to clip the rope into it.
So for sport climbing or normal multipitch climbing get the quickdraws with thicker (easier to hold if needed) 20 - 30cm flexible sling (avoids the drag and it will twist around when back clipped) and normal size carabiner so it is comfy to clip the rope into it.