The marketing plan is the overview of multi_channel approaches you should be implementing to develop and retain your prospects. It may include a call for brand development and demand generation as well. If your existing strategy is somewhat successful, but you want to grow _ the marketing services it recommends may be more focused on customer relations _ such as social media marketing, email marketing and telemarketing services.
Strategy _ similar to business strategy, marketing plan will capture strategies required to support your business strategy. For example if your business goal is to achieve 20% increase in sales, your marketing strategy would be to 1) introduce new product, 2) increase price for premium offerings, 3) recruit more distributors and offer commission scheme and so on. Strategy is king. When you can see your business in totality, I can assure you that you will find it easier to manoeuvre. Marketing plan is the place to address all these issues.