How to Cache ?

[Sama34]

I wrote a plugin, the problem is that iw will do the queries each time the page is visited.

The plugin shows the users lastpost avatar of the laspost in forum lists.

Can somebody, taking into account I have never cached something, explain me how to do it to increase performance? As I want to expand it for threads avatars and so on.

Thanks.

Here is the finished version:
http://mods.mybb.com/view/ougc-avatar-in-forum-list