Once you have surveyed your room's conditions and made any necessary "fixes", you can begin the installation process of your crown moulding. I would recommend the use of a CMS (compound miter saw) like the DEWALT DW716 15 Amp Double-Bevel CMS It's a good saw for cutting just about any type crown. I've owned a DeWalt 705 for about 12years now and I have nothing but good things to say about. I think it's a great saw and a good value.
I would also recommend a SCMS (sliding compound miter saw) like the Makita LS1013FL 15 Amp 10-Inch . I've owned a Makita LS1011 for over 15 years along with my Hitachi C8FB2 9.5 Amp 8-1/2-Inch SCM
(18 years now) and a just recently purchased a
Hitachi C10FSH 10-Inch SCML. This saw has become my saw of choice, but these are all good saws that will stand proud in any trim cutting task you might ask of them.
Another saw that I would recommend for this if you were really going to do large crown and wanted to cut it in position would be an Hitachi C15FB 15 Amp 15-Inch Miter Saw (No Bevel). This is a great saw for cutting large crown moulding. I've owned one for about 20 years now.
Once you have decided on a saw to cut your crown you might want to either make a work bench or purchase one. One of the most over looked "tool"s is a good solid work bench. In the past, I have gotten along just fine using a WorkmateTM. I would just clamp my saw down to the table and use an adjustable support to support the crown as a helper. Recently I have used the Hitachi UU610 Universal Miter Saw Stand and this stand works well, it's light weight and easy to setup and take down. If you are so inclined you can purchase a workstation like is one made by DEWALT DW723 Miter Saw Stand
and I'm told it's pretty good even though I haven't used it. Once you have decided on the saw and work bench you will still need a few other tools to help your installation go smoothly.
You will need the coping saw to cut coped joints. The plane, rat tail rasp, riffler rasps, chisels and four in hand rasp to "dress" the cuts of the cope to get that perfect fit. The knife to help "pare" down the wood and the bevel square to help measure inside and outside corner angles. The chalk to "snap" straight line on the wall or ceiling if you need to.
The first thing that you do is snap two lines on the wall, you do this by holding a piece of crown at its correct position between the wall and ceiling coming out of an inside corner.
You then flip the piece around onto the other wall and do the same. This will give you "guide lines" to follow so you can keep the bottom of your crown at the same relative position on the wall.


You do the same for any outside corners so you can have a line that goes completely around the room.
One of the simplest ways to check inside and outside corner is to cut four pieces of crown, two pieces about 16" long with a 45° inside angle and two pieces with a 45° inside angles. You will use these as test pieces to check the angles of your corners. You should try and make them as long as you can afford because the longer they are the "truer" they will represent the corners. If you place the test pieces into a corner and the joint remains open, try cutting a 46° angle on each pieces and see if the joint closes. If the joint is closed but the backs of the test pieces are off the wall, try cutting a 44° angle on the test pieces. Keep adjusting the test pieces until you have a good fit.