From a hardware standpoint, there is nothing that you can do to make it faster. With a SSD it should not exhibit any lethargic tendencies. Obviously upgrading RAM or the CPU is out of the question.
Though not specifically designed for your needs, this comprehensive trouble shooting document may provide you with hints as to what to do and not to do.
https://discussions.apple.com/docs/DOC-3521
What ever you do, DO NOT install any third party applications that promise to 'clean' your MBP or enhance it's performance. They are not needed and more than often will be detrimental to performance.
Ciao.