How can I make my self more desirable for retention/promotion?

Look better on paper and in person that your peers and those in the rank above you

You can never really 'max out' your civilian education. Yes you can only get so many promotion points for SGT and SSG but it will pay dividends to have a Bachelors or Masters when you are looking for the Sr NCO ranks. It might be that one thing that puts you above your peers. I also found taking some classes towards a management degree helped me in many ways later in my career.

As well you probably are going to want to sit down one day and figure out what it is you want out of your military career. If you want to do a full career in the military do you want to stay enlisted? If so how far up the chain do you want to go? Not all of us can become a SGM but if that's your goal then you need to do things to set yourself up for that. Eventually you will need to look for the assignments that will set you up for the best shot at that. Would Drill Sergeant help? Recruiter? Instructor? Schools are nice and can be a discriminator between you and peer but a successful tour in a challenging assignment will get you selected even faster. If your goal is to become a Warrant or a Commissioned Officer then you need to make plans towards that. That does mean Bachelors for the most part for Commissioned Officers and typically making SSG with ALC for Warrants. Once you decide what you want it will become much clearer to what you need to do.

Sounds like you are in good shape. Keep pushing on your APFT and if there is some sort of special school you'd like to attend, ask for it...like Combat Life Saver or maybe an ASI for your MOS. Other than that, stay out of trouble and start looking towards what you can do at the next rank.