MGE to DMG & DMG to LE is one of the hardest rank up to get.
One thing I learned is that you really need a 5 man team and no soloing once you get to DMG. I'm part of a group that play office on competitive we have around 6-7 teammates that share the competitive plays, TeamSpeak is a must, learn the maps your going to play smokes, flashes and one key point "WARM UP".
I have played many games with no warm up and my k/d ratio is shocking, however once we switch from either CT / T on half time my kill ratio changes. Last night we were loosing 11-4 on Office starting on CT, I had 2 kills to 10 deaths "ouch". switch to T side and ended drawing 15-15. my kills were 22 - 15. I'm currently ranking at LE but most team players are on LEM with one SMFC, there is no difference in skills from LE/LEM to SMFC accept for flick shots and pre-firing.