1. Find your laptop’s exact model number.
2. Look up the maximum amount of memory and memory type.
3. Find out how much memory you have now.
4. Add or replace RAM.
5. Find out if you can add another drive to the laptop, and which type of drive it takes.
6. Add an external drive if desired.
7. Upgrade the video and sound cards if they aren’t attached to the motherboard.
Source: Wiki How