The following steps will help you to write a good Marketing Plan
1. Situation Analysis – Where is the company now, you need to do a SWOT analysis here.
2. Objectives – what are the companies objectives over the next whatever amount of years, what is your purpore in writing this plan.
3. Strategy – How will you acheive the Objectives
4. Target – Who is your audience
5. Tactics – using the 4 P’s. Product, Price, Place and Promotion (or extended P’s People, Processes & Physical Evidence) How will you acheive your objectives?
6. Resource – What resource will you need
7. Measurement – How will you measure, against objctives, and gather feedback.

Hope this helps