It's a crucial rung on the ladder to the chief executive's job. It's vital that you make a convincing and confident start. So how do you avoid an embarrassing stumble?
Identify the key players. 'You need to find the centres of gravity and the centres of influence so you can build coalitions and networks that will be in place at 9am on your first day,' says Brendan McCann, a senior consultant at Mercer. 'What are the different agendas people have?' You need to build relationships with the finance director and other group-level directors - eg, marketing.
Look in the mirror. 'Take a hard look at your strengths and weaknesses and work out where you need somebody else to balance these out, and which aspects you need to work on,' says Mark Thomas, head of the strategy and marketing practice at PA Consulting. Enrol on a leadership development programme, and find a mentor.
Audit the business. 'The business units will be in a variety of states of health and you need to relate to them in different ways,' advises Thomas. 'With a sick unit, try for a positive intervention. As divisional director, you're much more likely to think of disposal. With a successful unit, concentrate on what will keep it thriving.'
Lead, don't manage. Says Catherine Bailey, director of general management programmes at Cranfield School of Management: 'You have to influence people well beyond your immediate group of reports, so use your visibility really well.' Adds Richard Dietrich, MD of coaching firm Praxis Management: 'It's not enough to worry about how you treat the people below you; now you need to worry about how they treat the people below them.'
Hands off. 'If you are constantly meddling and not letting your managers manage, they'll conclude: it's not really my budget, my strategy - no wonder I missed my numbers,' says Thomas. 'Yours is largely a coaching role.'
Broaden your horizons. 'You have to be an organisation leader,' says Bailey. 'That means you have to let go of what you've done well in the past, build relationships outside your area, and build industry-wide knowledge.'
Give your left brain a rub. Running a division needs more than just political skills. 'You'll need to put your emotional intelligence to work,' says Dietrich. 'It's essential to understand the motivations of other people so you can create an empathy and get them to work in collaboration with you, rather than in opposition.'
Do say: 'This is an opportunity to see how we can drive performance in each business unit while developing a successful long-term strategy.'
Don't say: 'I'm in charge now ...'