I attended a seminar back in November by a very good consultaint on Workplace performance, his name is Jason Womack. I took away many things but like everything else only a few end up sticking, or making their way into the workflow. The one that is proving very useful and very simple is the WaitingFor Folder in Outlook or any mail clients.
The concept is simple - when you send an email and you need to keep track of the content of the email for some reason or another, like you're asking a question, you need to know about something or whatever, you bcc yourself and you add a rule that when you're in the bcc field it gets routed to the WaitingFor Folder. This way when I send an email that I know there is chance I might need to follow up on - I bcc myself. So on a weekly basis I make sure I review what is in the folder, and I take actions from there, create a task, or send a reminder. For me it works well because I used to create a task after sending the mail, or taking a note or worst of all making a mental note I needed to revisit this issue later. This way the regular review of the folder does this automatically for me, and it saves me stress and time. Give it a shot!