Just last week, I was doing a test flight for a friend on his new bird. For me, the first flight is not a time to see how it does aerobatics. That will come later. It's to get the plane safely into the air, trimmed and back down in one piece.
To that end, my routine for a test flight is:
1. Instead of my normal, set the brakes, run it up, and release, I'll take much more runway, and slowly work the throttle up doing a very long roll on the take off roll, to creep up on funky ground tracking issues that might show themselves if the toe-in is not correct on the landing gear.
2. Once in the air, the first lap, is simply, 'fly the plane', even if it's way out of trim. Best to not get behind the curve if you have problems, and focus on just flying for that first lap or so.
3. Get the gear, and flaps pulled up and start trimming the plane. Take as many laps as needed.
4. Once trimmed, redrop the flaps, and confirm if there are any unwanted trim issues in that flight mode.
5. Gain a lot of altitude, drop throttle to idle, then back up 3-4 clicks (will make recovery much faster on the engine). Slow the plane and creep up on it's stall. On last weeks test flight, I noticed, it buffeted a bit, 5-7 seconds before it then broke hard and stalled. Stuff like this is invaluable to learn at altitude, instead of when flaring for landing at 10 feet.
6. If any time left, get just a few cruise laps in to get comfortable with the plane, then when time's up, do a good gear pass to confirm the gear are down. Start this process with a couple minutes to spare, as there is a decent chance the first one or two landing attempts might be high / hot, or slow / low, and require a go around, as the glide rate / sink rate of the plane is not known yet.
7. Setup for landing, and as on the stall practice, when you've solid for making the runway, drop to idle, then back up 2-3 clicks of throttle. Having a small amount of throttle in it, will make very little thrust difference, but will almost cut in half the throttle up time, if you have to punch it and do a go around.
8. If you're flaring for landing, and the plane is going back up in altitude, it's still going too fast, continue to hold it off, until it settles, mains first, even if it's further down the runway than you'd prefer.
Lastly, have fun and good luck !