Lots of good suggestions here.
- Practice while stopped, then work into it rolling after you're confident you have the technique down. Into neutral when clutch is engaged, into the lower gear just after the blip.
- Brake with the ball of the foot, roll to right and blip with side of heel. E9X M3 pedals are perfectly spaced from the factory.
- If you really want to become proficient after you've done several schools, the Bondurant Advanced Road Racing School will get you there. It's fabulous.
- Practice every day on the street. Choose a couple corners you can take spiritedly on your daily commute, and keep doing it so you don't lose it.
Never leave a car completely stock!