SEO isn't something that is so simple that you can change one page and you are going to be good to go. Realistically, without those back links, I generally don't even think about SEO. My main focus is marketing without SEO first, and then marketing with SEO later... I always have my site optimized for indexing and such once it does happen, however, I think that you really need to develop your site first, and then when it is truly ready and fully tested and you know it's definitely at it's best potential, that's when you really need to focus on SEO.. this way you'll reap the maximum benefits from it. That's how I do it, I know it's not the most popular way, however, I have been able to achieve much higher results with clients because of doing this backwards approach.