I have often seen business plans with great vision statements covering their sales, marketing, delivery and ambitions along with a complicated financial forecast that looks and sounds great however they lack a broken down target by target action plan, incorporating all the visions statements into easily doable activity.
So, make sure when you create a business plan you go the extra mile and list out an action plan. Each target on your action plan should be assigned to an individual. The individual as part of the management team would be the person responsible for the implementation, and would have to report progress at your monthly management meeting.
This not only keeps the momentum going but also helps individuals and/or teams to hold focus on what their particular role is within the plan.
It is often better to get others involved in your plans; whether that means telling your friend about them or involving employees on larger scale business plans.
This way the friend/employees will help you keep track by simply asking how the plan is going or offering help on finalising actions for example.
This will keep the plan fresh in your mind and so it will be harder to forget your drive and goal.