I have a few Aerotech kits which are built...even have the Strong Arm, which has been on my build pile for a while, but just haven't gotten to it yet. I think it's a great first mid-power kit and the SA looks awesome as well!
There are many tips out there if you do searches, but here are a few good ones that I know of from my experience:
-Get the needed supplies. Aerotech kits usually suggest CA (super glue) for assembly. If you're not used to it, learn about it before you send yourself to the hospital with your hands glued together or glue in your eye (I hear it's like a piece of sand that doesn't go away).
-Read through the directions before you start and lay out all the parts to make sure everything is there. Then don't lose any parts.
-Test fit the fins to the fin mounts and sand if the fit is too tight. I had trouble with my Arreaux when I added CA, then tried to snap the fin in and one didn't go all the way in. Terrible mess, but I got it almost all the way in just before the glue dried solid.
-I really worked hard on my Cheetah, but did a speed build on the Arreaux (tried to get the Arreaux ready for last launch last year, but couldn't attend). For the Cheetah I filled spirals and a number of phases of sanding and priming and it looks fantastic. I didn't fill the spirals in the Arreaux and while it looks good from afar, the spirals and rush paint job are noticeable up close. You often get out of it what you put into it. Filling spirals and doing a good paint job pays back lots, but can really hurt if it gets damaged.
Good luck with everything and I wish you a great build and launch!
Pics of my "Chester Cheetah":