Download the manual and read it often.
Take what you learn from reading and try it in the field, then make mental notes and write them down if you can remember to do so.
Learn every program and what it does - you will usually find you like Deep, Fast, Gold Field, Wet Beach, but this will depend on your conditions.
Learn how to customize all those programs and save them to new save slots and then use them at each of your sites.
Use each factory program at each new site and see how they differ.
Use Full Tones, five tones, pitch for experimenting with new settings.
Always ground balance.
Learn how sensitivity affects the detector on different sites, ie: I found that reducing sensitivity to 80 with the HF Elliptical coil didn't (seem to so far) affect my ability to detect any small objects, but it quieted the machine down when I run at very low (-6.4) discrimination.
Don't underestimate the power of the Audio Response - Run it in 4 if the conditions allow. Simply changing this from 1 to a higher number will make a massive difference in which signals come across as dig-able.
Remember to check your expert options in each of your programs for something you might have missed if you think you are getting weird results - you may have tweaked something that doesn't work for the site you are on and saved it.
When in doubt, go back to a factor program and start over based on what you learned from reading the manual many time and take notes.
Understand how changes in frequency can affect your site.
Go back to your sites using a totally different program and see what happens - you will likely get different finds and learn something in the process - take notes.
I've had my Deus for almost 2.5 years now and just bought HF Elliptical coil and feel like I have a new machine and get to re-learn everything based on the new coil - I'm having a wonderful time.
