Reduce stress in your life if possible, it can negatively impact memory:

https://en.m.wikipedia.org/wiki/Effects_of_stress_on_memory

Get more meaningful (and the right amount of) sleep, lack of sleep or too much sleep will negatively impact memory as well:

http://www.health.harvard.edu/blog/little-sleep-much-affect-...

You are exercising regularly, right? If not, you may be missing out on a subtle way to improve your memory as well:

http://www.health.harvard.edu/blog/regular-exercise-changes-...

What are you eating in your diet? Reduce the amount of foods - like steak - that increase LDL and change your drinking habits to increase or decrease your alchohol consumption to one drink a day:

http://www.health.harvard.edu/mind-and-mood/boost-your-memor...