September is a unique month for fishing. It's starting to cool, but those water temps can still be way up there.  If you check tournament results for September, the weights are usually low, so you can figure that it is a tough month to catch big fish. 

Follow up:

I like September much better than August because it is one month closer to October when fishing really picks up.  I recommend trying something a little different when going fishing in September --try fishing small creeks either wade fishing or floating.  It can be great fun.  Select creeks that are clear and low and you'll be amazed at how far a bass will move to eat your lure.

One of my favorite lures is the Culprit T-Rex fished weightless.  It moves naturally through the water when retrieved with short twitches of the rod.   I like to make it "walk the dog" for just a few feet off of the bank then burn it back in and cast to another spot.  Many bites will come as soon as it hits the water as these bass are extremely aggressive and competitive with other bass in the area.  Bass love to hang out where the current is hitting the bank head on.  This current is washing the food right to them.  There may be some fish all the way out of the current in little cuts.  If there is any cover in these cuts, fire a Culprit Pro Frog in there and hang on!

If you go to a lake, the water is almost stagnant this time of year so I recommend the moving water of rivers and creeks that flow into the lake.  Start your search with shallow crank baits and look for stained water in reservoirs.  If it is a lake with vegetation find current near vegetation; it can even be wind driven.  If you find a few fish, go back and flip any cover you find with a Fat Max worm.