The standard time lag for follow-up calls or emails is 1 week. If you're really in a hurry about something, add a line to the *first* email you send, saying "I will contact you later this week to discuss this further." Then you can email or phone after only 2 or 3 days, and say, "Hi. I sent you email about [writing class or whatever] on Tuesday, and I was wondering if you received it, and if you had any questions about that?"
That gives your contact the chance to say, "what email? I didn't get any email from you? where did you send it?" It also lets them say, "I'm not working on that project anymore. If you're interested in that sort of thing, you should call so-and-so." If he's contemplating it quietly, he'll say, "Yes, I received it Tuesday. We won't be making any decisions about that until November, but I'll get back to you as soon as I know something." And at least you know something about timing you didn't know before. A single follow-up is not pestering...repeated follow-ups with no response is what feels like pestering.
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That gives your contact the chance to say, "what email? I didn't get any email from you? where did you send it?" It also lets them say, "I'm not working on that project anymore. If you're interested in that sort of thing, you should call so-and-so." If he's contemplating it quietly, he'll say, "Yes, I received it Tuesday. We won't be making any decisions about that until November, but I'll get back to you as soon as I know something." And at least you know something about timing you didn't know before. A single follow-up is not pestering...repeated follow-ups with no response is what feels like pestering.