Maple is one of the harder woods to stain and keep the color uniform. When I stain maple I make up this very diluted sealer, of sorts. You mix 9 parts lacquer thinner to 1 part cellulose lacquer. Mix this up and apply with a rag or a brush or spray. I usually use a brush, theres no need to worry about brush streaks becuase the product is so thin. Let it dry, which won't take long. Give it a light sanding (very light as not to remove the sealer you just applied) and then apply your stain. What this sealer does is fill in the more porous parts of the wood, these porous areas are what gives you that blotchy finish you often see with maple. I do this every time I stain maple, among other woods.
Good luck, man