Sales is the most important part of your business plan. Not every part of your business plan is equally valuable. Some are more important than others. When you first start you business, it's important that you stay focused on sales.
Sales Business Plan
You sales model will change over time. I know so many business people who make a business plan thinking that is exactly how they are going to execute their business. They have a 2 year plan and expect it to go exactly as planned. This will almost never happen.
In fact, the part of your plan that will probably change the most if your sales plan. You can't know how, why and who will buy your goods and service before you go out. In fact, I don't know many businesses that knew who their customers ultimately would be. Yes, you do need a starting point, especially if you want to do sales lead generation to start out with.
Doing Sales
It's great to have a plan, but it's not good unless you execute it. This is where many people get stuck. They can't seem to be able to get over this hump.
You could always hire an outside sales rep to do your sales for you, but that's not always the best idea. In fact, you need to go out and do sales so you know what's going on. You don't want to hire out something that you should be intimately involved with.
If you are not good at sales, instead of hiring a sales rep, you should find a partner who is good at it. The best pairing in a start up business is a technical guy and a sales guy. One guy to know the guts of the business and the other to sell it. It's a very important lifeline for your business and the future of its success. Make sure it's something you prioritize and focus on.