You can run it off the web (I have not tried this and have heard it still has "issues") or download it here: https://www.sketchup.com/download/all (you'll need to create an account or use a google account).
Some comments from Steve:
Anyone else have some tips or tricks?I love Sketchup - I haven't done ANY kind of project, whether it be furniture, guitars, outside structures or even a complete remodel of my shop without starting with a sketchup drawing. Even things that I have full-size plans get re-rendered into a Sketchup drawing so I can make modifications or understand construction details that can't be easily visualized from a 2D drawing.
As to tricks or techniques, yeah, perhaps a few, but it's always a matter of being concerned about trying to teach your grandmother to suck eggs - you never know what other folks know, and risk insulting them with some stupid thing that they already know about, or something they've discovered how to do but with half the effort that my technique uses.
That said, I would say the most important tip is to find and install the Bezier Curve plugin. Can't do musical instruments with only arcs and circles. The other thing is to model complex curved surfaces by using Bezier curves as a guide, then simulating the surface as a series of triangles (all curves in Sketchup are actually a series of short line segments, each of which has end points and mid-points to which you snap the lines). Depending on one's patience for it, you can either get a complex curved surface somewhere in the ballpark, or damned close to exact, but it's a very tedious process. You can see an example of an "in the ballpark rendering" in the heel of the pic I just posted. I have another drawing of just the neck where I attempted to model a volute. Much more difficult, but I at least got some reference lines to work from when carving.
I've taught Sketchup classes to guys in my woodworking club, and would love to pass along whatever may be of value to others, subject of course to the concerns I mention above, so if anyone has any questions I'd be happy to answer them. I'm assuming that many others in this community also use Sketchup.