Do you have any issues, or are you just looking for general preventative maintenance tips? Here's what I suggest:
Software:
Keep the operating system clean. Practice common sense when browsing the web and downloading software. If you are interested in a questionable software program, check reviews or with us before installing. When installing, avoid unwanted bundled junk buy unchecking it in the installer.
Avoid big name antivirus software such as Norton, McAfee, etc. These programs slow down your computer and cause more harm then good. If you have windows 8/10, it already includes Windows Defender. Ensure that its on and updated.
If you have windows 7 or below, install Microsoft Security Essentials, a free, lightweight antivirus software.
I also recommend the free versions of MalwareBytes Antimalware and CCleaner. Install these programs and run them on default settings periodically. Remove any junk that they find.
Hardware:
This depends on the type of computer you have. But here's a a couple tips:
If you have a desktop or laptop PC, keep them clean! Keep the vents free of obstruction and clutter. Periodically use canned air to free up dust in a laptop's air vents. If you have a desktop, take the side panel off and carefully clear dust away from the components.
Use a quality surge protector or battery backup unit. You want a consistent level of power flowing through your devices to keep them healthy for a long time.
And finally, if you have a laptop, do NOT open the lid with one hand from one side of the screen. You use one hand in the center of the lid, and open slowly. I see people damaging their computers this way on a daily basis.
Anyway, just some friendly tips. If you have any specific questions post them so we can answer them.