1. Check Yourself
In 1975 Gerald Ford tripped while exiting Air Force One and was from that point on considered a klutz. The sad thing is Gerald Ford was probably the most athletic president of all time. He played football at Michigan and is the only president to ever tackle a Heisman Trophy winner.
You can save yourself the ridicule of being known as a klutz by checking the following before stepping out to the on deck circle.
Make sure your laces are tied so you don't fall face first into the dirt while walking up to the plate.
Don't have a bunch of seeds, gum, or other stuff in your mouth. Literally choking at the plate is far worse than choking figuratively.
2. Loosen Your Muscles
When I say loosen your muscles I'm not suggesting you get into a downward dog or some other yoga pose in the on deck circle. However, you probably want to loosen up a bit before you start swinging. This can be especially true if you are a DH. I mean lets face it, most DH's can hit a ton, but you guys aren't the most nimble or agile of the bunch.
3. Practice Swings
When I played baseball I always liked to take practice swings while on deck. I always tried to time them to the pitch as the pitcher was pitching. However even following this strategy I got out about 65% of the time. Or in baseball terms, I hit around .350. In all seriousness, you should make sure you are taking legit practice swings. Last thing you want to do is have a bad habit form as you step to the plate.
4. Stay Focused
Our brains are pretty advanced, but one thing that we are not very good at is multi-tasking. Unless it is chewing gum while walking, our brains are downright terrible at it. To stay focused on the pitch I always found it best to start clearing my head of everything not baseball related when I stepped into the on-deck circle. If you find it hard to clear your head, try humming to yourself, it is a trick speed readers use, but it also works for clearing out distractions.
Observe the pitcher. Pay attention to what type of pitches are being thrown, the strike/ball count, the timing, the placement of the ball and how fast the pitches are being thrown. All of these observations will help you at the plate.
6. Remember it is a game.
Don't take baseball too seriously. You will have many at bats in your day. Most of all never let someone tell you what to do to get ready for the pitch.
7. Be Alert
Be on your toes. Most on-deck circles are placed on the playing field, leaving players vulnerable to being hit. Pay attention to where the ball is at all times. When you are taking your practice swings make sure you are not taking them at the same moment as the batter at the plate. This way you will be prepared to protect yourself if a ball is hit your way.