1st thing would be a shroud, then probably a Telrad or Rigel, both a far easier to use than the supplied 9x50 finder, especially when observing anything near the zenith when you may end up on a step ladder ( depending how tall you are ). The head of a 2Kg lump hammer and magnet may be useful as well if your planning to use any heavy eyepieces and you can stick it to the mirror end to balance the weight out.
I also fitting a cooling fan to help speed up mirror cooling ( approx £20 at the time ).
Dew prevention and eyepiece choices can wait until your used to your set up and know what your likely to be targeting.
Ian