1.) What is the single most important thing to know about in retail?
1(A) Cash flow. Most new small businesses don't make it past year one because of inadequate planning and management of funds.
1(B) Customer Service. Get it right and you'll go a long way. Get it wrong, you won't survive.
2.) What high tech communication, informations systems are used by your company currently?
Sorry, can't help you there, I'm completely online now, but remember one thing: simple is usually better.
3.) Define leadership?
Some interesting definitions here
4.) In your eyes what are key areas that effect profitability?
It goes without saying that you need your stock to move as fast as possible, but for pure profitability, build good relationships with your suppliers and always negotiate the best deals possible, without compromising quality or service.
5.) How do you assess/evaluate your employees. How often? What criteria?
There's only one criteria: Results! Employees should know clearly from day one what is expected of them, you should recruit people who are capable of doing what you expect of them (or be prepared to train them), and you or their line manager should be motivating and guiding them all the time (read: every day, every hour, every minute) to achieve those results. This is especially important in a retail environment. Your staff can either be your biggest asset, or your biggest liability.
Best of success with your venture!