Since your application is unknown, as is the frequency and desired inductance/turns ratio, that's about all I can provide. The ARRL site has lots of info on such stuff.
One thing to add in winding the toroid, make yourself a bobbin or shuttle to wind the wire on first that you can then pass through the toriod core easily. Don't try to do it by just pulling the wire through, unless you are making only a very few turns. A narrow strip of circuit board makes a nice shuttle. John
There are quite a few different materials used for toroids; they have different permeabilities and are used for different frequency ranges. The material used is generally (but not always) indicated by coloring the toroid's coating.
I downloaded a "cheat sheet" from Amidon last year which was a fortuitous move; it no longer appears on their website.
There are formulas on this "cheat sheet" for number of turns vs inductance depending upon the material and size of the core.
I have attached it as a .ZIP file; it is a web page in .mht format. You should be able to un-zip the file and then view it with your Web browser.