I have several websites, probably more than most people.  I find it extremely hard to keep up with it all.  I have done some organic search engine marketing but you have to keep on top of it, and it is just too much for me.  Every once in awhile I will have some free time to work on the sites.  They stay at the top of sites like Yahoo and Google naturally until I forget about them and have to start all over again.  I recently started to get more related links on my site and that is working for now, I just have to keep at it.