Pokemon GO players can use Gyms as lucrative coin farms. Here are some tips on how to make gyms and position less vulnerable to attacks
Establish Gyms that are located in areas where the GPS signals are weak or intermittent. This will usually discourage potential gym attackers. For your part, look for a top spot or higher grounds where you can get a much stronger GPS signal.
Set up Gyms in places where there are not much people and traffic around. It's lonely but at least your coin farming will not be disturbed. It will also be better if the gym could not be reached by any motor vehicle. Those living in the city would have to make an effort to find such place but those in the countryside will have no problem setting up this kind of gym.
Set up Gyms in areas where your Pokemon GO team are strong. Gyms that could only be held for a few hours will not yield many coins. If you want to venture out, start at the borders and inform your team mates about it so that they can help strengthen the new gym.
Deploy top Pokemon Gym defenders to discourage as many attackers as you can. Some of the best Pokemon GO defenders include Dragonite, Exeggutor, Lapras, Snorlax and Vaporeon but other Pokemon with the highest CP possible would do.
Put Pokemon on the top list and high level gyms. Make sure that your Pokemon are not listed in the bottom three. Pokemon GO players should at least aim for the fourth spot form the bottom because it will take 30,000 prestige points to knock you out from the spot. Do not let opposing Pokemon GO gyms flourish in your stronghold.
Pokemon GO gyms are also a great source of Stardust. The more gyms a player holds the greater number of coins and Stardust can be collected. Make sure to check each gym at least once a day.