gps - use for reference only and not as a main source of navigational aid. I suspect many night time accidents are caused by captains getting fixated on the screen and becoming complacent with night time navigation skills. Contrary to what you may think as a new boater, night time navigation is actually better with lack of visible lighting around you. IE make sure cockpit lights, dash lights and anything else in you vision range is turned down or off. Your 360 lighting and stern lights should not be visible to you while under way and this may take some adjustment. Docking lights (headlight lookin things if ya have 'em) should be left off while underway, these are for docking and are illegal if used while under way.

Learn how to use a map and compass, if you loose a gps in open water you then have no reference to where your at.

I will echo (again) the USCG boating safe seamanship course. &/or Powersquadron course.
Have Fun!

Tools and tool boxes - heres another little tip i came up with years ago when trying to determine exactly what tools i should keep on the boat. This takes time to perfect and will change from boat to boat. Start with a basic set of what you think you need. When you work on the boat weather it be on the trailer or at the dock use only tools from this set. Through time add things as necessary and pull things that arent used. In time you will have pretty streamlined set and not near as much as you would think.

Spares - keep an extra fuel/water filter and also a water pump impeller kit. I keep a small spare electric fuel pump as well.

plenty of life jackets and make sure everyone can swim . extra cell phone battery,flares day and night, epipen or benadril you never no when a bee or jelly fish will sting you

Definitely bring DOUBLE the amount of beer you expect you need. If you and a buddy normally drink a case (while you have a sober driver of course) at a BBQ, bring two.

When you pull the plug, let it drain and put it back in immediately. I imagine this is how people forget to put it in.

Buy some trash bags to keep on the boat. It pays off.

Hit big waves at a 45 degree angle, it's much smoother and you'll break less stuff in your boat.

When you're finally ready to a) launch the boat or b) trailer the boat, relax and walk around ONE MORE TIME to check on everything. You'll be surprised how often you find an issue.

watch somebody launch a boat before you do and or have somebody help you the first couple of times.

I would actually advise against putting it back in, put a sticky on the dash of the tow truck that says "DRAIN PLUG!!"

I've done both, left the plug in and after a couple bad days of rain almost sank my old checkmate on land
And backed the same boat in, parked my truck only to see it sitting about 6" too low, got it out quick but both times were to close for my taste, stuck the note on the dash and eventually it was second nature

My drain plugs get stored in my truck's driver seat back pocket, with my keys that lock the trailer and coupler. When I go to hook up the boat, with said keys, the plugs go in.

Congrats on the new boat!

A few tips from a relatively new boater:

1) Ensure that your fuel gauges are working properly.
2) Learn how much fuel your boat consumes.
3) Take your time! Launching, docking, rafting, trailering - rushing any of these leads to silly, costly mistakes.
4) Never take boating advice from anyone who has never owned a boat.
5) Finally, use your boat and use it often.