Hey Blue Bomber,
I've recently started blogging too, though not just about running (www.stratium.co.uk)
My advice would be to stick as many photos up as possible to break up the text. All my posts (except the most recent one!) are quite heavy on photos/light on text and this was all from photos I already had before I started the blog. I think now that I'm doing it I'll concentrate on taking better photos when I'm out and about too.
Personally I'm treating the blog as something like a diary; I'm not actively pushing it to get traffic, just waiting to see if anyone turns up really!
http://www.petesy.co.uk is a very good example of how to blog well, check it out if you get a chance.