Just thought I'd clarify some terminology here. It's extract with steeping grains,partial extract is another expression for partial mash. Both are different processes.
Having said that,getting the right crush for any kind of grains will help not only efficiency,but keep that floury,misty stuff suspended in the fermenting beer to a minimum.
Temp control within the middle range of the yeast will give better results. The lowest possible temp for a given yeaast ime is a bit too slow,just a step above stalling if it dips down for some reason.
Clean & sanitize everything that touches the beer/wort,no matter how small or insignificant it may seem. Bactria/funguses don't need a lot of room.