What I have figured out is, 99% of the time a bluegill takes your bait, you will feel multiple little bumps. Sometimes they will pull and it may feel like a bigger fish but it is just the bluegill trying to not let the prey get away. If it was a bass, you will feel heavy weight that doesn't move. as soon as you feel the weight and start to pull up slightly to figure out if it's a fish or not, it will pull back much, much harder then a bluegill. One thing I have heard that has really helped me is "hook sets are free, don't be afraid to set the hook. Use them as much as possible". If you set the hook, I tend to pull straight up instead of going to the side. Setting straight up will guarantee a hook set instead of a side hook set which has the chance of pulling the bait out of the mouth of the fish.