Couple of quick plugs and things to look at, probably more useful for newer players but everyone should take a look:
Jersey General - The linked post makes a good case for Chaos Space Marines as a good starter army. It's good to know that sometimes good things can still come from Jersey. ;-)
N++ - Good article about saving old paints. Sometimes you don't use a paint for a while and it needs a little TLC. Poke around, other good guides here too including good intros to some common hobby tools.
Elf'n'Happiness - Simple and effective idea for a home-built deffrolla. Reminder that bits can come from many places, not just sprues.
Creative Twilight - A reminder not to be too timid during games. Even as a new player don't be afraid to try things; it's the main way of finding out what works!
Table Top War - The linked article is about Space Wolves vs. Blood Angels, but even if you don't play or plan to play one of those, taking a similar look at your own army could be a good idea. If you see another player doing well with X type of army, it can be tempting to try to recreate that with a different codex...but it's often not a good idea.
40K for the New Professional - Good article on some ways to keep yourself on track when tackling a large project like building and painting an army.