I went 15-1 in 3.5 this year playing singles
In Combo I have gone 5 - 0 in 7.5 and didn't seem to have any problems playing against the high ranked partner on the opposing side.
I have a pretty big serve, forehand, with a solid backhand. My biggest weakness is I am slow and even though I have been running(3 miles 2-3 times a week) a lot over the last 1.5 years, I would say my stamina isn't the greatest.
Is there anything I should particularly focus on in preparing for my bump up?
Continue to improve your best shots. Work hard on your weaknesses. Work to become more aggressive--find ways to win the point, rather than wait for
your opponent to give it to you. Play against stronger players. Have fun!