Yes, You Can Get A Financial Life!: Your Lifetime Guide to Financial Planning

I would suggest putting in at least as much as your employer matches. Preferably more than that, given that it seems you getting a later start on the 401k savings than many people.

This book may be helpful: https://www.amazon.com/Yes-You-Can-Financial-Life/dp/1401911...

EDIT: As always, beware financial advice from random strangers on the internet. :-)