For my Birthday this year I got a copy of Tilly and Buttons 'Love at First Stitch' (Available here). I have since decided to sew up a whole lot of work clothes for Summer from its provided patterns. I started with the Clemence Skirt, basically the book just tells you how to make the pattern. Very simple stuff and is identical to a skirt I made myself when I first started machine sewing nearly 2 years ago.
You have your simple waistband (waist measurement + seam allowance), skirt length + desired width.... For me that is usually however much fabric I happen to have left. Sew it all together and add in a zipper and done.
Check back later on for my versions of other Love at First Stitch patterns.