The most likely reason is that you are running too many high powered devices on the same circuit at the same time. Turn off some devices to reduce the load.
Another reason could be a short circuit or ground fault. If you smell burning wires, leave the breaker off and call an electrician.
A faulty appliance may also lead to tripped breakers. If a breaker trips, check the appliances on that circuit and see if any appliance is hotter than usual. If so, call an appliance repair person.
The AC condenser uses a lot of power upon startup which can drain power from other loads such as light bulbs. This is usually a normal occurance if it is brief and the lights don’t completely turn off. Upgrading your main service may or may not help as the power company’s transformer and power lines feeding your house are the limiting factor.
GFCI monitors the amount of current flowing from the hot to the neutral wires. If there is an imbalance, it trips the circuit and protects against electric shock.
AFCI breakers trip when an arc in electrical current is detected.
LED lights consume less power than incandescent and fluorescent lights and are therefore better for the environment. LED lights come in various colors ranging from bright white to warmer shades.