It all begins with the proper clay and manta moisture levels for packing. Preformed mound bricks are a good way to shore up landing areas when frequent maintenance is not available.
That is a highly variable question based on level of play and maintenance plan. However, some basic principles are to make sure that clay:silt ratios are 1:1 and that the mix is clean and free of debris. Inexpensive soil tests can help to determine what you currently have and adjustments can be made from there.
Aerate worn areas monthly and spread seed immediately following. For a permanent solution, install synthetic turf on batter walk up paths and the rim around the batter’s circle.
Use batting practice mats when possible. Aerate that area monthly and spread grass seed immediately following. Grass may be pre-germinated to speed establishment.
The best offense is a good defense. On a weekly basis, rake infield dirt from the grass edge back into the infield dirt using a stiff steel leaf rake. On a monthly basis, blast built up dirt using a water hose and adjustable pressure nozzle. If dirt build up is more than 1”, use a 21” sod harvester and cut out one width of sod around the infield grass edge and replace with new sod.