Diving is first and foremost a PRACTICAL skill so the best way to practise is to do it. Yes you can read through the books to refresh your theory, but this will not refresh your ability to dive. But it can be helpful in reminding you about small things you may have forgotten. Practising hand signals can be good, but these we always confirm before dives as different divers from different places and different organizations might do dive signs a bit different.
My suggestion is that you go for your first dive with a Divemaster/Instructor or very experienced diver on a nice easy shallow dive so you can just work through setting up gear, getting used to the feel of the gear as you swim (achieving Neutral buoyancy), breathing slowly and deeply in and out without holding your breath.
Also remember to practise things like mask clearing, regulator recovery and clearing as these are things that happen more often and should be easy and effortless to do.
If you been out of diving for a long time with very few dives it is worthwhile to do a whole refresher course with a qualified instructor to refresh all the skills you learned. This should be done in a pool (or very clear, calm, shallow ocean) followed up by a nice easy ocean dive.
On the theory side I would recommend going through those adventure dives that you might be interested in doing and that have a bit more to them to think about: DEEP, NIGHT, WRECK, etc.