Colours yes 100% I think I'm going to make a song to try and remember them haha, same with the substitution colours but you can learn how to do ligand substitution and precipitation equations because:
-the amount of ligands that are substituted into the complex is the same as the charge on the ion
-for NH3 and OH-, OH- is substituted into the complex
-BUT in excess ammonia 6 NH3 are substituted in
-AND Cu(H2O)6 does partial substitution with XS NH3 so makes Cu(H2O)2(NH3)4 (I think it is the only one that does this)
-Cl- ions almost always make XCl4 complexes
Right I think those are the rules, if you learn those and do some practice questions you shouldn't need to learn all the reactions