I'm excited about transitioning from straight up kick boxing to Muay Thai.  The most difficult part so far is the transition from throwing a hand - mostly hooks - and not returning to my peek a boo guard.  I spent a lot of time making sure that I didn't drop my hands or leave them hanging out, but I now I want to have a more open stance with the traditional Muay Thai hand position.  The kicks seem to be coming easier, but I am staying low until I feel like I hitting them most of the time.