Sgt_Kickaxe - 10:40 pm on May 13, 2010 (gmt 0)
These days you need to build sites like a christmas tree. Your biggest and brightest site being the star and each subsequent site being a branch lower on the tree. Each branch down links to the one above it once or twice to funnel pagerank up the tree like sap.
If you can add outside links to branches consider them ornaments, they often break in time.
Another way is to run a web directory. Submit sites that link to you into the directory, don't link to them from your site. You create a mini tree out of them, they boost your star and the directory boosts them.
The internet is a Christmas tree!