1st lets take a look at what they eat. Bluegills feed on worms, insects, crustaceans, and minnows. The small bluegills feed more so on insects and the smaller crustaceans like scuds. While the larger bluegills go after bait fish. Do not, I repeat do not think the big ones will not go after insects. They will. Especially when over population is in place. These fish will eat whatever comes their way.
Although matching the hatch can provide some great fishing. (Matching the hatch is a term used when you match your fly to whatever is flying around in the air.) Dry flies like irresistibles, humpies, varrants, and just about any Adams pattern will do the job just fine. you may also want to try a small terrestrial such as ants, beetles, or hoppers. A variety of streamers and wet flies will work well to. You will soon learn which pattern you prefer and which works and doesn’t work for you. I personally love the Adams fly. even if you tie and fly that you might not feel is the best I suggest trying it anyways. More than likely you will catch something with it. Bluegills as I mentioned before are not picky eaters. They will take just about anything. This is exactly why they are so much fun to catch.
Your fishing outfit should not be over complicated. You do not need a new rod or a fancy reel. Just whatever you use for trout fishing will do just fine. The only thing I would rec commend would be to use a lighter leader. Other than that your trout flies will do. Now go catch some fish.
With the beginner in mind I would suggest to someone who has no gear. Get a 5-6 wt rod. Some people may tell you different for bluegill fly fishing but trust me they are wrong. With a 5-6 wt rod you can have fun bluegill fly fishing but will not need new equipment to fish for trout as well.