This is a good question and if you ask 100 seo’s for an answer you will likely get a varied response.
Here’s my thoughts:
I like to put my links to my other sites at the bottom of my pages. is that hurting me?
– No, this should not hurt you so long as the se spiders can access the links.
I’ve heard its better to have one way links to a site than recips; so I’ve been thinking I should link some sites to some, others to others; and as i understand it; make sure there isn’t a loop made in the process.
– Links are funny… good themed recip links will likely carry more weight than non-themed crap links (ala blog spam). All things being equal, one ways are better… but, I figure the se’s are looking for a natural looking link pattern. If you only have recips with the exact same anchor text, then it appears un-natural. The same goes with one ways etc. Try and vary your anchor text, and your ratio of one ways and recips too. You can achieve good results ignoring this idea, but it takes a lot more links to get the same results as a varied link plan.
Good luck trying to create a scenrio where the se’s cannot detect a “loop”. I think they can find patterns pretty easy, whether they want to “punish” for link schemes is another story. I’m thinking that planned link schemes are worse than just random link tactics.
Last thoughts – Google seems more aggressive than the others for punishing or not counting crossed linked sites etc. Yahoo seems to be more forgiving of these things.
BTW – This stuff is highly speculative and no one knows for sure. I am telling you this based on my experience, and it may be different from what others have seen.
Good luck!