A common mistake when managing large projects is over-planning at the beginning and then under-planning from then on. We're fixated on the need for complex giant charts and detailed assumptions which are exactly that, just assumptions.
Once the project is a few weeks in, the chances are things will change in the wider world - and the more complexity in your original plan, the more work that leaves you to unpick and change. Work against your intuition and plan with just a small number of important milestones. Focus on getting the right initial 'black and white sketch' in place, but don't paint it with colours until you're underway.
Review, update and refine more regularly
The above tip only works if you follow this next one: review all of your projects at least weekly. Use a checklist to help you define what you need to think about each week so that it becomes an effortless habit to constantly assess progress and plan the next steps. Don't be afraid to change direction or react to what's happening around you. Being nimble, reacting to events and being proactive by injecting new is usually better than being thorough and meticulous.
Communicate to solve problems or create momentum, not just to communicate
Avoid, if possible, the regular 'project catch up meeting'. Yes, do them occasionally, but resist falling into the trap of everyone feeling like the meetings are a drain on their energy and time every single week, otherwise you'll quickly build resentment. Use meetings only to solve problems or create momentum. Communication is important, but it's a means to an end, not the end. Save peoples' time and input for where you really need it - and don't forget that when you don't, you can still maintain the momentum that by making sure you're reviewing progress on key matters via phone or email.
Every action needs an owner and a deadline
The enemy of so many projects are 'we' and 'ongoing': 'We'll do this'. 'This aspect is ongoing'. The problem with such vaguery is that you can't measure progress. Ensure that every action and every portion of a project has a single owner: one person who will be responsible and accountable for making that thing happen, to a specific deadline. And define 'that thing' too!
Control is a feeling not a goal
Feeling in control has nothing to do with how much work is still outstanding or how far you're behind! It's totally possible to feel comfortable with complexity, as long as you feel in control of it and know there's a route through.
Our gut reaction when we feel like everything is spinning out of control is to rush in, frantically get things done and try to 'save the day'. Unfortunately, to feel in control actually requires the opposite. It requires us to quietly take a step back - to reflect, refine, re-plan and repurpose. We have more control over our minds and therefore our stress levels than we do over our complex projects (!) but luckily by seeing things more clearly, we're better placed to take more decisive action.
Graham Allcott is the author of 'How to be a Productivity Ninja' and founder of the productivity consultancy Think Productive.