Rinse daily after use, brush off any external grit or grime as needed, dry and then spray or wipe down with a light coating of a dry lubricant to expel any remnant moisture and to coat the external components with a protective barrier against salt and sand adhesion. If the reel becomes submerged for any period of time or surf spray is extreme, you will want to make sure the gear cover and rotor are removed and dried separately, and the inside of the gear box is not contaminated.
Once a month, it is a good idea to add some oil to the more accessible bearings. Remove the handle and handle screw and put a drop or two of oil on the exposed bearings on either side of the reel. Next take of the rotor assembly and put the same amount of oil on the exposed bearing. I’d also put a couple drops of oil on the spool shaft.
As a preventative measure, I recommend the reel be broken down, cleaned and serviced before seasonal or extended storage or at least twice a year (every 2 months if fished an average of 4 or more times a week).