How to make printing run faster?

Printing can be an easy job if everything goes smoothly, but sometimes it runs very slowly. There are some reasons:
1. Insufficient memory
2. Limited free space on harddisk
3. System infected by virus/worm/trojan or spyware
4. Printing too large file.

Then what's the solution?
You can increase your computer memory, delete some unused files on your harddisk, run defragmenter, scan for viruses and lastly convert your files to another format and try again. These are common solutions to slow printing problem.