I mixed the paint with water in some areas to get a watercolour effect. The sash was made from silk, so the paint reacted slightly differently to it than it did on the synthetic: it's a natural fibre and absorbs water more - you can see this in the second image. Water also darkens the silk, so you don't know the exact outcome until everything dries. The synthetic resisted water, so it was easier to guess the final outcome. The markers worked best on dry fabric, and blended great with the paint.
I was running behind, so I took the markers along with me to the wedding and worked on it on the floor the day before. Finished it up by ironing everything, so that the paint was set and wouldn't run if it got wet. It's a good idea to cover the fabric with some cotton and then use the iron, rather than having the iron placed directly on the painted fabric.