What can I do, my 2012 MacBook Pro is too slow?

[iMore Question]

My brother gave me his MacBook pro 2012 which if found running very slowly from past few days. I think that my Mac OS X was better than Windows system, but it doesn?t. I also do some basics hard drive space optimization, but nothing worked for me.
System specifications: 4 GB of RAM with 500 GB hard drive space, OS X Yosemite.
What steps should I perform to improve its performance?

 

[robertk328]

The 2012 is the last model you can upgrade yourself. I would make the RAM at least 8gb and add an SSD to replace the slow hard drive. It'll be like a new machine with those updates

YouTube has the videos to do the upgrades.