Online: login through myAES (the link also found on the right side of the AES home page). Insert your Login name (your AES ID#) and password; select My Transactions, scroll down to Memberships and find the Renew link, and proceed to check out.
To change your membership type, you will need to contact email@example.com, as this cannot be done online.
An electronic receipt will be sent to you upon completion of this transaction. Be sure not to hit submit more than once or your credit card will be charged again. (You'll know if this happens if you receive more than one receipt).
You can renew for 2 years at a time, but currently, must complete the above transaction twice in order for your membership to renew for a 2-year period.