It's important to have pre-formulated questions and some preformulated answers; these will keep you on track and remind you of the important things you must either ask or say about yourself. But don't forget to truly listen to the other person. A conversational flow is much more effective in terms of learning about each other and gauging a fit than rigid,
Send the interviewer a follow-up email. Thank them for their time, but don't use this as another opportunity to sell yourself.