n account executive is in charge of managing customer accounts. Basically, it is a fancy word for "salesperson"!
What you would actually "do" depends on the company. Some companies would hire account executives to manage existing accounts while others would expect you to generate new business (most would probably be a combination of existing and new customers).
No matter what the industry, account executives would be most strongly involved with something called "the personal selling process"...I've held "account executive" positions in several fields and have friends in others and universally, we all received training on the selling process and then applied it in our jobs.
The personal selling process involves seven steps:
1. Prospecting and qualifying prospects -- locating potential new customers and determining if they are in a position to buy what you're selling. Cold calling is one method of prospecting but there are many others. For example, some companies use telemarketing (or advertising) to generate "leads", then account execs take over and finish the selling process. Qualifying prospects involves things like checking someone's credit, making sure you're talking to someone that has the authority to make the decision, etc...).
2. Preapproach planning -- getting ready to meet with the customer (new or existing). Involves research to find out relevant information. For example, you might need to know what the company does, the name of the decision maker, and what your product can do for the company (what are the company's needs).
3. Approach -- first contact with the customer. Involves building rapport (for example, looking for common ground)...first impressions can make or break a sale.
4. Sales Presentation -- this is where you make your sales pitch...tell the customer what the product can do for them. In some fields, this is "canned" (a memorized speech/presentation)...in others, it is "creative" (salesperson adapts pitch to needs of customer). The latter is much harder AND usually much better paid!
5. Handling objections -- objections are reasons the customer can't buy...money, mood, too busy, competitors better/cheaper/whatever). A good salesperson learns how to counter a variety of objections to motivate the buyer to buy!
6. Closing the sale -- getting the signature! Often overlooked...often requires salesperson to ask for the sale (directly or indirectly). This is the toughest part for many people since a common rule of thumb is that you have to hear 9 "nos" to get 1 "yes"...lots of rejection.
7. Followup -- often forgotten but goes a long way toward building a long term relationship...repeat customers are MUCH more valuable than new customers esp. to salespeople. If you follow up to ensure the satisfaction of your customer, they'll come to you next time and you'll have an easy sale!