Cleaning to prevent rust starting

[Rob H]

My 89 coupe appears to be in fairly good shape and I want to keep it that way.
There seems to be no visable signs of rust in the normal places and no evidence of accident damage, just stone chips and some respray in the middle of the doors. I am sure it must have had some minor scrapes repaired but it is pretty good.

I use the car as a daily driver and for track days. It sees dirt roads very rarely but I live on the coast, literally(marina frontage) and keep it under cover at home and work.

I am not fastidious by any stretch but would like to keep the car for a long time, so was wondering the best way to treat it so that rust does not develop in the usual spots. Just hosing underneath or high pressure? Removing any panels and cleaning behind anually? Using any products? Are there drains that get blocked easily?
Any advice would be appreciated.

Rob