Before delving into solutions, however, it's a good idea to get an overview of the extent and source of the problem. You should view your site from a variety of computers to make sure the slowness isn't just something particular to your internet connection (like a slow computer or ISP). It's also a good idea to visit at different times of day/week/month and so forth. A brief slow-down that occurs infrequently is much less of a problem than chronic lag. Of course, some times may be more important than others for you. If you have a Christmas themed site, for example, it probably won't console you if it runs fast January thru November, but lags badly in December.

After confirming that there really is a speed problem that needs to be solved, here are some questions that might help in coming up with a solution:

(1) Is your web hosting service to blame?

In particular, if you notice that not only your site, but every site that is serviced by your web hosting provider is slow, it might be time to upgrade to a faster host. There might, of course, be some cost to increasing speed in this way. A free or very inexpensive host might not be as measure up to one for whose services you pay a little more. (I have been very happy with the cost/speed of the hosting provided by Futurequest).

(2) Is it your whole site dragging or just certain pages?

Obviously if you have some pages that load fast and others that don't, it makes sense to look at what differences exist between the two to see what might be changed to speed up the laggards.

(3) Are too many (or too large) pictures causing a problem?

A few appropriate pictures can liven up a page, but every picture adds to the time it takes for the page to load. A lot of pictures can mean a lot of loading time. A single huge picture can be just as bad. You might want to reduce the number or size of pictures on the pages to speed things up. By all means, use compressed images such as gif or jpeg to cut down on file size!

(4) Is some other site's slowness affecting your site?

Anything that your pages pull in from some other (slow) site can cause things to grind to a halt while your pages wait for the object to arrive. Video, advertisements, and pictures can all do this. If an element you really don't want to get rid of is exhibiting this behavior on one of your pages, you might consider at least moving said element toward the bottom of the page, so that the items above the offending element can render in the browser first.

(5) Are your pages just too long?

Text renders fast in a browser ... well, most of the time it does. Even text can cause a page to dawdle, however, if there is enough of it. Maybe that blurb you wrote that runs on for thousands and thousands of words can be split up into several smaller pages. They'll load faster, and your visitors won't have to do as much scrolling.

It's possible that applying one or more of the preceding ideas may be all you need to do to accelerate a lethargic site. In other cases, particularly if your site is complex or unusual, more effort and research may be required. Either way, be sure to back up anything you'll be changing in case the changes have unanticipated negative consequences and you need to undo them.