I work at an LFS...well, sorta, it's Pet Supplies Plus but I'm that 'resident fish expert' and we sell plenty fish. Some tips for getting the right kind of help and staying on the right side of the employees (maybe make this a sticky, hehe.)
1) Look around before you ask for help, especially if the employees are busy, (like at a general pet store, i.e. Pet Supplies Plus or those other two that start with P...can't remember.) When you simply look around and the employee can only watch you for 10 minutes and they have other things to do, it's obviously annoying. If they ask you if you need help, you can tell them you will in a few minutes.
2) Be interested in what they tell you about the fish or things that you should get for the fish. Otherwise, you give off the feeling that you don't care about your fish and if it lives or dies. Even ask if there are any special foods or what the LFS feeds - even if you already know.
3) Make a point to stop by even when you don't want to buy any fish. This way the employees get to know you. There are about 10 regulars I know by name. They ALWAYS get the heads up on new products or fish and I always give them the most care. Their "1 dozen feederfish" are actually more like 16. They get a lot of discounts on supplies as well.
4) Don't expect the greatest customer service if there are 3 people waiting in line behind you. It just works that way.
I've been catching fish all my life, so I move the net pretty swifly through the water and catch the fish in a few seconds. For the slower ones, I just put the net in the tank and lift up from under the fish.