Besides installing W3 Total Cache or another caching plugin what steps can I take to make sure that my theme and site run as fast as possible.
You could install WordPress on Nginx. There are a number of resources to help:
Some performance information from that last link (which appears to be a bit different setup than the others):
So I decided to put a proxy in front
of wordpress to static cache as much
as possible. ALL non-authenticated
traffic is served directly from the
nginx file cache, taking some requests
(such as RSS feed generation) from 6
pages/second to 7000+ pages/second.
Oof. Nginx also handles logging and
gzipping, leaving the heavier backend
apaches to do what they do best: serve
dynamic wordpress pages only when
On nginx – it’s so efficient it’s
scary. I’ve never seen it use more
than 10 to 15 meg of RAM and a blip of
CPU, even under our heaviest load. Our
ganglia graphs don’t lie: we halved
our memory requirements, doubled our
outgoing network throughput and
completely leveled out our load. We
have had basically no problems since
we set this up.