I think it helps if everyone takes turns leading a dive and being responsible for keeping track of everyone and watching pressure guages. It gives you a sense of where you want people to be and how you want them to act. I dive with some divers that like to the follow the leader. I'm pretty good at looking through my fins or over my shoulder, but I would prefer my buddy to be on my side so that I can simply turn my head. Consequently, when I am the "follower" I'll try to keep the plan straight in my head so that I can anticipate where were are going next and head in the appropriate direction without getting behind the "leader" (we are running parallel courses).
If I stop to look at something interesting, I'll look, them swim past it and stop so that my buddy has a chance to look at it too. For example, we might be peering into portholes on ships, so I'll wait until they had the same chance that I had. If there are several in a row, then we will work them simultaneously, but I'll check their positions between portholes. Waiting for them to catch up is a good time to regroup and make sure everyone is still tight.
Also anytime, there is a change, such as a depth or course change, it is a good idea to regroup everyone and signal the change. I'll also check pressures a few times towards the beginning of the dive so that I can gauge the relative air consumption of my buddies. If I dive with them for a while, I'll generally have an idea where there pressure should be relative to mine and looking at their gauge is just to verify my calculation.
Lastly, I'll physically look to see if they are still where I expect them about once per minute. This is a quick glance- as long as I can spot a fin or light or even bubbles above where they should be, I assume they are OK. Less frequently, I'll do a "full OK" where I will look them over, signal OK, and give them a chance to signal OK or communicate anything else.
I tell people that I dive with that if they have a problem, stop and I'll come to them. So far it has worked out. At first it might feel a little paranoid always looking for you buddy, but it makes the dive exciting and at the same time, you can relax that you know where they are.
Edit: forgot to add- when I do the "full OK" I'll look the over to see if they are flailing around, breathing hard, having difficulties with gear or clips, or have eyes the size of baseballs. Anything that might indicate they are uncomfortable!
This whole process should go both ways, regardless of who is "leading" and who is "following."