That's good advice, but that's what I need help with. I don't know how to look into database optimization, CDN, etc. Where should I go to find someone to help? Are there forums, or services that do this?
You could probably hire a free-lancer to get most of this stuff going for you (there are plenty of sites around for hiring people to do small jobs).
Ultimately, though, you should look at trying to do as much as you can yourself. The better you understand your system, the better you can run your company.
Still, CDN and database optimisation isn't the first place to start. As I mentioned, look at YSlow, which should give you a few places to work on for optimising your sites.
As mentioned by someone else, depending on the technology your sites are running on, there may also be plugins/tools available to speed things up with little to no real effort.
Anytime I need to figure out how to dig deeper into a technical problem, I start with http://stackoverflow.
A lot of questions like yours have already been asked with hundreds of great responses. Just spend an hour searching around for database indexing, using a CDN, and writing better sql queries and you'll have pages and pages of invaluable information at your fingertips.
