We subscribe to MSDN, SQL Server Magazine, SD Times, and another good one is Code Magazine.  Most of our tips and tricks come from a lot of experience and just digging it out.  This is the type of stuff that we try to relay to our users through our training classes, and when an opportunity presents itself, on the forum.  There are a lot of resources, but regardless of the resource, you always have to figure out what is relevant to your development style.