Cut chicken breasts into chunks. Usually I plan on one normal sized breast per person. Place chicken in a zip lock bag or other container. Cover with Italian dressing - don't be stingy! Let it marinate in fridge for at least a couple of hours.
Cut bell pepper and onion into large pieces. I usually quarter the onion and then separate the layers.
When skewering the chicken and vegetables, I always make sure that there's a slice of onion next to every piece of chicken. It really does make a difference!
Grill the skewers on medium to medium high for about 15 minutes.