I would follow some principles that worked in my past.1.)
Don't miss the moment
The integration is starting now and well before you are signing any agreement.
You should communicate the whole plan to all level of organization.
Ideally you should have a well trained and motivated team in place with clear responsibilities.2.)
Get your attitude
From day one you should make decisions, effect changes and set goals. Never be indecisive.
To make bad decisions is better then 'no decision'.3.)
Declare pre-closing goals
Important to review all assumptions correlate them to actual facts found in the new organization.
Clearly and concisely set expectations.4.)
Understand in-place business plan and processes
Never assume that existing processes are wrong, nor ignore to change to "used to do on this way in my company" without good reason. If you cant make it better don't change it.5.)
Communication is critical
Go over of your way to over-communicate. Be honest. Don't try to be clever or mysterious. Talk openly.
Immediately do everything is necessary to assure customers, suppliers, distributors and employees that business will be conducted without disruption.
Be available. Everyone on integration team must be available in24/7.6.)
Built up tense of the team
Make sure everyone's expression of speech show unity.
There is only one way - OUR way. No 'My way', 'Your way', 'Our new way' or 'Improved way.
Only OUR WAY.7.)
Set clear management structure
Make difficult decision early to dismiss senior management, if appropriate.
Consider promotion of subordinates to position with higher responsibility. This could bring out the best talent of people.8.)
Divide actions to short-term, medium-term and long-term phases9.)
Last, but not least ..... KEEP EVERYONE FOCUSED ON CUSTOMERS.
