If I have to create a file from scratch I do it this like this....

1. Get Audio file, load into Cakewalk.

2. Listen to file. Attempt mentally to isolate the drums, bass, vocal, strings, brass, etc etc tracks as separate entities and sing/hum along to each distinct part. I am lucky here; I have always been able to play by ear; what has improved as a result of formal musical training has been by ability to quickly recognise the "jazzier" chord structures.

3. Create basic drum track and use to create a tempo map by hand. I have never found the automatic tempo map creation option in Cackewalk to be any use.

3. Having created tempo map, get drum track spot on.

4. Add in Bass, Vocals, Strings, Piano, Brass, Guitar, etc etc tracks

If the guitar work is very strummed, I tend to copy a strummed passage from another style / midi file and adjust. As a keyboard player I am not good at "Live" strum guitar tracks, they always sound like "This is a keyboard player trying to sound like a guitar"....

After this, refine until satisfied.

Sometimes I find I have to stop trying to be "note perfect" and instead go for "feel perfect", in other word I know the notes may not be totally correct but the overall mood created by the file is accurate.