My advice would be to make sure that you are organized from the start.
Set up campaigns right away for every program that allows it so that you can get an accurate picture of your traffic. This will be priceless down the road when you have hundreds of web pages on your sites and need to analyze your stats to see where your traffic comes from.
Create a contact database that lists affiliate managers and other affiliates. Never buy, sell or use emails address that you did not collect via an opt-in method. Start collecting emails via your site from day one.
Be very careful when using your domain name to register at sites (even affiliates sites). I’ve found that the email I use for my affiliate account is the one that is spammed the most! Use a free email and then redirect it to yourself. Don’t setup generic email names like admin, webmaster or names that can be guessed by spammers. That way you can utilize your catch all folder for spam.
My advise as it relates to SEO is start early and be prepared to read alot. DON’T assume the information you read is accurate until you see it repeated on different sites. Don’t pay anyone to do it for you because this is the most important part of your business and you need to learn how to do it yourself.
Try to attend the affiliate conferences. If you can’t afford to go then start making a plan to work with one to two programs that you do well at and have a good relationship with the affiliate manager and give them your best exposure in exchange for sponsorship to the event. Make sure that they will go for it first.
There will be times when you will be totally overwhelmed and frustrated so you need to have something to reward yourself or to remind yourself of the goal.