The follow-up is continuing to offer valuable solutions to your prospect's problems. You have to be consistent in this process. Your ideal customer is not going to have JUST one problem. They initially are trying to solve the problem that is immediately in front of them. Once you help them with their initial problem, they will look to you for help with additional ones.
This is also why it is extremely important that you continue making yourself valuable by educating yourself. By becoming a learner, you are becoming a leader that will be sought after by others.