Practice in your backyard.
Use coins, all denominations and jewelry and (trash), scrap bottle caps, nails and aluminum pull tabs from soda cans.
Put them on the ground about 2 foot apart and listen and watch the screen as you pass the coil over each object.
Then put the trash objects near the coins and jewelry in small seperate areas.
Once again, listen and watch the screen as you pass the coil over each object.
After you have done this for a bit you can try using the discriminate button to knock out the undesired objects.
Practice alot in your yard before you go out on your first hunt and learn your machine and then you won't waste your time or pass up good finds when you go out to the better places in your area.
Learn to dig a proper plug in your yard before you go out to a public park and make a mess which will anger people and will eventually get metal detecting banned from the park.
To cut a proper plug after you have pinpointed an object, take your digging tool and cut a circle in the ground about 6-8 inches round. Keep the digging tool straight up and down and not on an angle when you are cutting the plug. Only cut the circle about 3/4 of the way around and then flip over the patch of grass.
(This method is used so all the roots are not cut from the grass so it will recover and not leave a dead brown patch of grass a few days later.) Place a smal rag on the ground next to the plug hole and put any extra dirt from the hole on the rag. When you find the object you are looking for, take the rag and dump the dirt back in the hole. Flip the patch of grass back over and then tamp it back down in place. When you do it right it would be difficult for someone to walk around the area and see where you dug your plugs.