Having a little trouble getting links indexed

I know that getting links is required for most websites, but as time goes by, the harder it seems to get all links indexed.  I have paid for links in the past, but it seems that less than a quarter even get indexed.  I think the reasoning behind that is because all "posts" are the same.  I think Google or other search engines can see that it's all the same and that they were all posted in succession, therefore don't index them.  I think I'm going to do a few more SEO projects by myself, then just outsource all the other projects out.