To avoid getting gas build up in your stomach drink and eat slowly and not fast.
When you eat and drink too fast you risk swallowing too much air which can increase the gas on your stomach.
Also try drinking some gas reducing tea when you fill a build up of gas in your stomach and fart when you feel the need to.
Avoid drinking beer or other carbonated drinks which can build up gas in your stomach.
Another thing that works to get rid of gas in your stomach is to apply heat to your stomach whether through a heating pad or a hot water bottle.