There is a huge difference between Sales and Marketing, but there is a very delicate balance between the two.
Thunder lets you know that there is storm coming but the rain actually touches you. I like to think of Marketing like the thunder and Sales is the rain.
You have to be heard, no one will buy your product / services if they do not know about you. So your customers have to know that you are out there - Marketing
You have to be able to be there when your potential customers need you - it is a numbers game you have to touch them and you have to do it frequently - Sales
Too many companies base their Sales objectives on what they need to sell to make the bottom line for the company. This is a dangerous game if you do not understand the needs in your market and how well you company's product / services meets these needs. On top of this you have to understand how well your competition addresses these needs - second place is the first loser.
Market Opportunities, Product / Service Preparedness and Your Competitions Preparedness all of the be considered.
It is a balance between understanding the market opportunities and how prepared your company is to address them.