What are the biggest concerns of doing Marketing/ business Plans?

When developing a business plan, there are many concerns that the Business Manager need to address in order produce an effective business plan, first of all the plan has to be aligned with the corporate business strategies, be able to achieve the business goals and objectives, must be realistic in projections and numbers for both forecast sales and costs in order to project accurate financial planning, your marketing strategy needs to offer an integrated communication plan utilizing both on-line and offline tools, you need to prepare the proper market research and competitor analysis in order for senior management to make informed decisions.
The market research part of the plan is what usually most business planners overcome, not realizing that neglecting this section can have serious consequences on the success of the plan, I wish your question was more specific in order for me to be able to provide you with a more accurate answer, these are some of the concerns but I am sure there are other concerns as well that I have not addressed in my answer.

معرفة احوال السوق وان يكون المنتج مما يحتاجه السوق وبشده وتكون للشركه استراتيجيه جيده للسوق والدخول لعالم التسويق الانترنت وعالم التسويق الشبكى لانها من انجح الوساءل

To me the main concern that in the market reserching stage and how we collect the right market information/intelligence to allow building our both business and market plan where leads to have wrong mission and vision to our business.
In general, some businesses don’t know how to plan.
Lack of a plan worsens even creates an issue at the execution for the cash problem by wasting cash chasing tempting diversions, and throwing money at problems.
Equally important is revising your plan according to changing economic and business conditions and to ensure your survival in the recession.