OK..first, is the problem with engine running or engine off? If when running, then you may have an electrical noise problem from te engine.

Check the battery pack. Is it able to deliver the current to power all the servos. Are all the servos good? How does it work if you use Futaba servos...sometimes, mixing brands of equipment can cause problems. Do you have good-quality servo leads and connectors? How long are the leads...do you have heavier-gauge wire on the longer leads. Do your long leads have RF chokes or ferrite beads? How close is the battery and servo wiring to the receiver and receiver antenna?

If you remove the equipment from the model and have the receiver antenna to one side and all the servos to the other, do you still get glitching?

There really isn't an official "checklist", you just need to start out with one thing and carefully work your way through. Unplug all the servos and see if you get glitching with one servo. Add the additional servos one-by-one and see when you get the interference. Maybe one servo is causing the problem. It may be that the Hitec servos you're using just aren't compatible with your receiver.