Granulars are usually easier for a startup company. Liquid weed controls, fungicides and insect controls usually are cheaper.
Liquid weed controls are usually better.
Timing: Follow the holidays for your area. Easter , Memorial day
July 4th( if you do a mid summer treatment) , Labor Day and Thanksgiving. This gives you pretty good timing and spacing between applications.
There are many websites with free information. In addition,
call your extension service for reading which pertains to your regional environment.
Common sense and an awareness that every year offers different
conditions will help you become successfull. Lean on the ones around you that you can trust for information. Go to seminars in the winter when you can.
Good luck!