On shorter rides or when the trails are all close to the parking lot, I just have a small under seat bag with a couple of tube patches, a small multi-tool, and a granola bar. I have
a frame mounted mini pump, and I use a Looney Bin bottle cage. It is adjustable and holds my Apex stainless bottle fine, even through crashes.
On longer rides, I use a hydration back pack. Similar to Rasheed's with more bars, and an extra tube, bug wipes, a rag and bigger mulit-tool.