Number one is preparation. You need to get yourself sorted right from the beginning. Make sure your ship's in order right from the beginning.
Make sure your stuff is in order and you understand where you're going. In many instances, the greatest issues have occurred from just a lack of clarity of what the goal is and what success looks like at the end.
What does success look like? Have you got your finances in place and do your staff know how to deal with integration and transition once it all happens? Get your deal team in place, make sure you've got the right pieces of the puzzle. People who've walked the fire before, understand what you're going through.