Welcome to the hobby, and im glad that we get to see another tank build! Yote is right about the aquaclear filter, but i would keep it if you dont have a fug running and stick some live rock, rubble and macro algae in there in order to have some natural filtration along with a place for pods to grow!
Aftershock is right, dont do impulse buys. This includes fish as they can crash your system if you put too many in at once, although, im probably the worst for this! my tank is 4 months old and I have everything I can get my hands on hehe. Often putting 3 fish at a time, then more the next week hehe. Whoops. Ive been lucky so far though and very watchful.
Thats the other thing, make sure you have a full set of testing kits for:
nitrates
Nitrites
Ammonia
PH
Phosphates
other useful ones
Calcium
Alkalinity
Magnesium
the other thing you can do is start planning what fish and corals you want in your tank, because with that size, you have to pick fish that fit, will be good to look after in that tank (food wise, eg. mandarins need lots of live food) and whether or not they will fight. Ask here, all bets are someone has been through what your asking and we always want to help :D
Best of luck with this :D and welcome to the empty wallets club.