One trick you'll definitely want in your bag is how to distinguish bottlecaps from coins...because some of those bottlecaps sound very very good, and much like a silver quarter. One way to do this is to setup two identical programs for your modern trashy park--one program will use 4Khz and the other 12Khz...make sure they're side-by-side in your program slots so you can easily flip back and forth. All the other settings for these programs are up to you and should vary depending on the type of trashy park....ask yourself, is there so much trash that I need reactivity 3, or can I get away with 2? R2 will get you deeper, but R3 or R4 will get you better separation--if the Deus sounds like a machine gun when you swing it, then you need R3 or R4...sacrificing a little depth as you increment upward--be mindful that when you change reactivity, the silencer changes automatically, so check that when you make changes...-1 is wide open, which is what I like. Further, is the iron level such that I can set disc all the way to 0 or do I need to cut out SOME of the chatter? Is there so much trash that I must use some notching, or am I willing to decipher those extremely low tones above iron and those really high tones beyond the coin range? Anyway, so you've got your two programs installed, now find a bottlecap and swing over it using your 12Khz program and note both the tone and the VDI. Now flip over to the 4khz program and do the same....
You'll notice that when sweeping over the bottlecap in 4Khz, the tone and VDI will increase....which is the opposite of what a coin will do. A coin's VDI and tone will decrease when going from 12Khz to 4Khz. I learned this trick early on and I've never found a coin in the hole when the VDI/tone increased when going from 12Khz to 4Khz--I've saved hours and hours of digging. Early on I didn't trust this method and consequently dug a lot of bottlecaps--once in a while I still do.
BE CAREFUL! In trashy parks you'll discover a lot of coins are partially masked by trash, so if you get even a hint that the VDI/tone decreased when going from 12Khz to 4Khz, then dig it. Sometimes the separation between coin(s) and trash is wide enough to make it an easy decision; other times, you'll find that you can only get the target's VDI/tone to decrease when sweeping at only a particular angle....that's when you dig and then boast about how brilliant you were to dig that seated dime. Good luck!