Here's a short article by Inc giving their thoughts on Six Ways to Speed Up Your Website.
Below are the bullet-points but click the link above to read the entire article:
2. Improve loading time of key page content.
3. Put style sheets at the top of the page content.
4. Minimize the number of HTTP requests.
5. Consider deploying Web acceleration hardware.
6. Make sure core content is not delayed by extraneous elements.