Don't speed up or get out of the bar-to-bar formation. Maintain a steady speed, squeeze through the gap and go to the front (see below). When the two riders ahead of you peel off, don't slow down and look around. Maintain your speed and go straight through without hesitation.
Rule 5: Too Tired to Go to the Front
If you don't want to go to the front, sit at the back and let the riders coming back from the front of the group slot in ahead of you. It isn't acceptable to work your way up to the front of the group and then slow down because you don't feel strong enough to be at the front.
If for whatever reason you do find yourself at the front, go through and take what is known as a token pull. You go to the front for a couple seconds, agree with the rider beside you that you are both peeling off, and go to the back.
Rule 6: Gaps
There should be no gaps in a group ride. As soon as you see a gap, fill it by riding into the space in a steady and controlled manner. There is no need to sprint into the space and then slam on the brakes, just gradually fill in any gaps as soon as you see them.
Rule 7: Moving About in a Group
If you need to go to the back of the group, or need to move away from the side of road because the road is damaged or obstructed, just steadily move in whatever direction you want to go in. The key to all group riding is to do things gradually and steadily.
Even if there is a rider right next to you as you pull out to the side of the road, if you do it gradually, the other rider will naturally have time to move over with you. If you do anything sudden you will likely cause a crash. This is also very important when peeling off and filling a gap.
Rule 8: Obstacles and Hand Signals
All obstacles should be warned of by a simple hand signal. When you see an obstacle in the road ahead of you, put your hand down and give a signal that lets the riders behind you know in which direction they should go to avoid it. Traditionally a quick wave of the hand will suffice. Most of your riding partners won't hear you anyway, and if they are close enough to, you don't want to startle anyone taking a drink from their bottle and cause a crash.
If you only see the obstacle at the last minute, ride through it! Better to get a flat than to take down the whole group. On the subject of obstacles, please only point out those that are worth pointing out.
"What obstacles are worth pointing out?" That's simple. An obstacle worth pointing out is one that will damage a bike or person behind you. Don't point out manhole covers unless they are deeply set in the road, leaves, small cracks in the road surface, or other objects that aren't truly hazards.