Good ole cable management. This is one of the most challenging skills to master.
Planning. Make sure you take your time to plan, take notes, draw diagrams, count cords and outlets, try to think ahead for the future and make sure you leave access to anything that need to be unplugged and removed to be clean, extra slack for things that need to be moved and maybe cooling depending how much your shoving into a small space. Excess heat is the number one killer for premature electronic failure.
You want it to look clean but still be accessible. If you get to permanent with it, could take up to a half a day to uninstall a simple pump and replace it.
I personally start with a count/list of all items. Take into account how many power bars I will need, what will need to be automated, what will need constant power, cord lengths, where the best mounting spot to protect from water.
Then what can be semi permanent, what will need 3 month cleanings, what I plan on upgrading in the near future.
Then try to separate water lines, electrical cords, and probes.
Cable management is a mentally spacial project, where foresight and patience are your friends. Plus looking at what other have artfully done will help give you a start and ideas.
Some amazing wire ups on here, but don't get discouraged if it looks overwhelming or does not turn out as well as others. It is a art, one that I will never master.