Do you love big bluegill?
In addition to what Josh said, I would also try and determine what the largest size class of male BG you currently have, and make sure to return those fish. The largest males keep the other males at bay, thereby delaying their maturity and causing them to grow larger. I second the notion of keeping females, unless they are extraordinarily large. I have returned two females in the past few weeks, but only because both were pushing a pound and I couldn't convince myself to toss em' out.
Pay attention to your fish's condition... are they long and skinny, with large eyes and an obvious, projected "nose"? Probably too many mouths to feed, and their growth is suffering. Those fish need to come out. When they look "tall", for lack of a better word, and their "shoulders" get thick and start to overshadow their nose, giving them a short, or flatter faced look, and their plump and healthy looking, then you know things are starting to work to your favor.
A general rule of thumb is to wait 5 years after the initial stocking of the pond. This allows the introduced fish time to mature and spawn. With each spawn over a five year period this ensures there is a good forage base in the pond. Also, what is your goal? Do you want to manage for big bluegill, big bass, or just all around good fishing. Each management choice poses a different set of rules. Let me know what your goal is for your pond and we will talk slot lenghths and overall helath of your population.
Thanks James, My goal is regular fishing for food and fun. Its not to get trophy size BG or LMB. I just would like to enjoy what I have. Now with that being said I do catch and release some BG that have shocked me with their growth rate.
I posted this same question on the pond boss site and the advise I got that I already started doing is harvesting several a week through out the season. Keeping all eating size female and returning brood stock and returning most males. I was told with the males whatever the average size of the large ones I catch return those and keep the ones that are about an inch smaller. So far its been working out. It doesn't seem like I am upsetting the balance any. And when I feed them. It doesn't look like any were even removed yet. I have been doing this for 5 weeks now. And today I removed 14.