ideas re: arranging time

Rght now I do sell Avon, and also take university courses.
Some days are just not good for making deliveries because of the
pressures on me to prepare for exams or get assignments done.
What can I say to people so that they will understand that sometimes
I cannot make their delivery "right now" - that they will have to wait
for a couple of days?
Most people will understand - but I do feel some pressure at times.

My thought is for you to bring up deliveries when the sales are being discussed. You could tell them you are in school and what you anticipate to be the approximate delivery date.

TheyByzantine has an excellent suggestion. I'd maybe work on the other end too; don't you know when you have tests/work scheduled so you can look at a calendar and give a date you will be free for delivery? Maybe you can pick a normally lighter school day and have a policy like, "I only deliver on Tuesdays" or something?

Has anyone complained about your deliveries or are you thinking in your own head that they are not good? That makes a difference :-) You are probably doing quite fine, especially if you're getting repeat Avon business; it's not likely they'd come back if they didn't like your way of doing business?