See how the ceiling in the photo above slants up in the right corner? This was not going to be easy!
Fortunately the crown moulding we wanted was on clearance at our local DIY store. Unfortunately they didn't have enough in stock and we had to drive to another location 1.5 hours away to get more. We went with a 5" crown that has a very detailed profile. It matches all of our original trim really well, so the drive was worth it. We are hoping to have enough left over to do the front hall as well (YAY! More crown moulding...).
The first thing we did was read and print off instructions from this blog which we found on Pinterest. She gives very clear templates for cutting inside and outside corners and how the moulding should sit on the saw for each different one. In the past we have tried to stand the moulding up to cut the angle, but with her instructions you lay the moulding flat on the saw. It was so much easier! We also purchased a handy angle measurer and printed off a list of mitre cuts for every angle imaginable. So with our angle measurer and the new mitre saw we got for Christmas, we were ready to go!
Installing crown moulding takes a lot of patience and precision. We literally were measuring twice and cutting once. We also always cut our pieces a little on the large side, because you can take more off but you can't put it back on.
So we're about 3/4 of the way through the room right now. We still have the bay window to do, which has some very interesting angles in it. Hopefully that goes ok!