I'm working on elvish language for my Avarthrel stories. Elves, of course, need to know write too. So here's the Obligatory Elvish Handwriting System. Probably looks kewl enough as an appendix to the book.
As for *real* use, note that this is just a quick drawing that shows the general letter shapes, not a downloadable font or anything - heck, it's probably not the final version at all. This obviously can still use some refinement. Also note that this just defines 6 vowel characters and 24 consonants, none of which are assigned (though I'm pretty certain I'll use vowel characters as a,e,i,o,u,y, as shown in the pic); I'm not even sure if the language needs that many consonants. Last I counted, I had 22, with some that are probably rare enough to be dropped completely.
As for guiding ideas - well, some Tolkien influence, of course, but also some systematic ideas from real world - *which* real world language, I have no idea, though just yesterday I was reading something about Chinese and Japanese writing systems. This is much simpler than either of those though.
The guiding principles are show in picture captions: 1 stroke for accent versions of the vowels, 1-2 strokes for stand-alone vowel glyphs, 3-4 for consonants.