Is it me or do things move a lot slower on here these days.
My biggest tip would be planning.
Ignore the urge to jump in.
Research the setup process fully. Then research it again. Then question your findings. By questioning every aspect you will understand the where's and why's much better.
Then compile a list of what hardware you need. Don't scrimp on the necessary items. Quality items will serve you better in the long run. Marine setups aren't a cheap hobby, but, there are many bargains in the classifieds or on eBay. Ask questions of sellers ifpurchasing 2nd hand goods. For example if you were to purchase a tank for reef use you would need to know the tank history. What set up was it used in? Any medications used? You don't want to fill a tank with invents only to find that copper from meds is leeching from the silicon. Good bye invents.
Make a weekly planner or flowchart of the setup and cycling process. Ensure that no steps are skipped or ignored through impatience. You'll be glad in the long run.
Plan the tanks contents. Rock, livestock, corals?
It may sound daft but if you know what fish you want to keep its also important to know which order to stock them in. Anybody who has tried to add a timid fish once your clown has claimed the whole tank will know what I'm talking about.
I would say the planning and diary keeping stage should last at least 6 months. Frequent testing of water parameters. The smaller the tank the more stringent the testing. Observe your inhabitants. Changes in behaviour can indicate an issue that needs urgent attention.
I'm either preaching now or rambling. Either way I need some sleep. Night folks.