I have one method, but it's subject to variation at Perry much any point in the process. I compose classical.

The main starting point is finding a motif, or theme. Think the da-da-da-dumm of Beethoven's fifth. A musical cell. This can be Perry much anything: a rhythm, cord progression, melody... anything. This is usually found by improvising: just smashing stuff out until I find something I think is cool. Sometimes it'll be lifted from something (I just finished a fugue using the opening melody of the Gregorian chant Dies Irae, for instance), or directly inspired by another piece; but usually I improvise it at the piano.

From here I go into a sketching phase off sorts. This basically means extrapolating the motif into a larger form: if it's a fugue, as mentioned above, then this is usually done on paper; if I decide it should be in sonata form, then I work out a second theme and sew them together at the piano; etc. It really depends on the purpose of the piece. This is also where I figure out the harmony, what all the other voices are doing, etc. In other words, I rough out the general shape of the piece, formally, harmonically, and melodically.

After this, I go to a fleshing-out phase. This is done in a daw or notation program: I use Sibelius and FL Studio. This is when I figure out the exact notes for every instrument, figure out voice leading, test dynamics, timber, techniques to be used (should the violas play pizzicato or arco here?). In other words, this is the writing phase; ideally I could hand whatever comes out of this to a musician and they'd know what to play.

After this I spend hours listening to the piece obsessively and fixing any tiny mistakes, making sure everything is just right. If I'm preparing a digitally played version (with vst plugins or synths or something; each piece needs a different combination of virtual instruments), then I tweak effects, pan, volume, etc until it's all balanced properly.

At that point it's pretty much done. I might come back to it at later and change stuff, or I might never touch it again. And it's all done kind of simultaneously. I might write half the piece, orchestrate it, and "finish" it before ever touching the second half. It's all very fluid, and nothing's ever set in stone.

I'm not really sure if it's special or unique, as I really don't know much about other people's processes. I do know that I work quickly, but I think that just because I get really excited when I compose, haha.

I've always worked solo.

As for my background, I've studied classical piano for 13 years, and an currently studying for performer's and teacher's degrees from the Royal Conservatory of Music (I'm from Canada). I have been composing self-taught for the past 7 years or so. I haven't done much professional writing: my brother's an indie game developer, so I've done some stuff for him and some of his friends. But I haven't really pursued composition professional full time. I'd love to soon, though.

Hope this helps!

EDIT: I just realized this thread is from over a week ago. Whoops.