TerryC is absolutely right!!! Put in at least 100 hours. Go to Youtube and type in "coin popping". The ACE 250 is good right out of the box but even better with 100 hours of experience on it. Look up my name and read some of my past posts. Also try crazyjarhead. He's great with the 250 and large coil. The finds from my ACE bought me my Garrett Propointer, a sniper coil, a Tesoro Vaquero, another Garrett ProPointer, and a bunch of misc. stuff related to detecting.
If your hitting local parks, learn the art of CHERRY PICKING! I was at a park that had a huge family event one evening. The next morning I was digging a clad penny that was 5 inches deep and in pretty bad shape when some kids were walking by me about 10' away and stopped and picked up a huge pocket spill of quarters!!! Now...I cherry pick a place first to get what's fallen close to the top. I re-hunt it later to get the stuff that's deeper. You are really going to LOVE the ACE 250. Feel free to ask questions here or with a PM. There's tooooooooo much stuff to put here.