Research and patience are the keys.
There are areas near me I don't bother with because plenty of other people know about them and search them regularly.
When I first started I was happy if I came away with 50 Cents.
I now look for parks and schools in older neighbourhoods and ones that are not visible from any main road.
parks on average will yeild a dollar or two if you find an unsearched one, schools have yeilded up to $10 bucks in change for the good ones.
I am very systematic and grid the whole area. I am one with my detector and know when signal is real or a ghost. I still dig the ocaisional ring pull and canslaw. Coins have a specific tone as does silver and gold once you learn these you can save a lot of time.
I use the pinpoint function religeously. I know to within a fraction of an inch where the target is so in most cases I can just slide my screwdriver into the ground and flip out the coin. For the harder tragets or in mulch I have a digging tool that will cut through sod like butter and fingers if you are not carefull.
I was the same when I got my detector I expected to find treasure. Its out there you just have to be patient learn your machine and 'Dig everything'.
I have a basic machine its an ACE250 and is described as an entry level machine. It does everything I could ever want but you have to read the manual and get to know it. There is not really any such thing as a switch on and go machine. I keep thinking a I would like to upgrade but why bother when I am finding stuff fine with the one I have. The only difference with a better machine is it will tell you with a greater degree of certanty what kind of metal you have found.