As a reseller of SEO services, you must strive to be the best at it that you can possibly be. There is too much competition to assume that you win just by offering it. So primarily, be an SEO reseller who values his clients. Just because you resell SEO does not instantly mean that what you do is better than what anyone else does. You still need to cater to your clients, and now you have yet another tool with which to accomplish this task. Take it seriously, though, or risk losing your clients to your competitors. That would defeat the entire purpose of you working with a private label SEO firm.
Be an SEO reseller who actually understands SEO, at least partially. Do not be one of those resellers who simply resells something because he knows it has value. Understand why it is valuable, formulate a pitch as to why it is so valuable, and then believe in that pitch. Realize what you are reselling, and use it in the best and most professional way possible. Your knowledge here is important particularly if a client has a question about how specifically SEO would benefit that client. Your answer will mean everything to the client here, and tripping over your words could indicate that you have less knowledge of SEO than you actually should.
Be an SEO reseller who joins the right kind of SEO reseller program. Do your research here, and do it well. Do not run any serious risks of picking out the easiest companies or the ones that promise you what ends up being too much or too little. The more extensive your research is here, the more likely you will be to choose from among the top SEO reseller programs today. Use your time wisely to research both how to pick out white label SEO providers and how to know the difference between black and white hat techniques.
Be an SEO reseller who demonstrates efficiency right from the very beginning. Understand what will change within your enterprise when you begin to resell this service, and plan accordingly for it. Do not just assume that it will not interfere with your other daily activities. It very well could not make a difference at all, but at least you will have planned for it. And be serious about your intentions as an SEO reseller. What do you hope to achieve through this? How much do you anticipate earning in the first year? What do you hope to throw on top of SEO as a reselling tool? Plan well, and your chances of being an excellent SEO reseller will be very good indeed.