I just started taking Dressage a couple weeks ago. My biggest tip is wear something comfortable lol. I have been riding in my western cowboy boots and jeans, and my calves are bruised and scraped up! Not to mention that it's a disaster to post due to my pants continue to ride up my leg. The saddles are different so leg placement is also different and where it sits there tends to be more metal. Sorry it's late and that's my biggest problem at the moment. Also take it slow and understand that you don't always put two and two together at first. Some things with the dressage you don't always get at first, like posting, and keeping quieter hands, full contact on the bit. Also you use your seat and leg pressure more than you would "steer" with the reins in western. That's all I got. Good luck and have fun!