Good work Lunalafey and Isthmus - you are rightly looking for connections.
Gemini on the tenth does suggest communications, but also writing, journalism, travel (short distances) such as road haulage or freight, teaching, advertising and sales, information collection and dissemination - such as Market research.
With the ruler Mercury in the fourth its possible that it could be a family business, or working from home, or using family property. In Capricorn Mercury is more structured, ambitious and cautious. So those may well be qualities you would bring to your business. You are more likely to remain single minded rather than be a fount of ideas but see none of them through.
The fourth house cusp ruler is only useful in so far as it may indicate the qualities of the home environment that might lend themselves to your career if you work from home, or family qualities if it is a family business.
Sagittarius brings a desire to expand an learn - to grow, through travel, learning of philosophies and undergoing higher education.
You may therefore have a home environment which encourages your personal development and is willing to foster a sense of adventure.
Sagittarius careers are more related to legal, clerical (in the sense of clergy), publicity, travel, import and export, forecasting, exploration - occupations that require some foresight and sense of adventure. Though I would not see these as a direct link to employment.
Sixth House ruled by Aquarius suggests that as an employee you will be independent, detached, quite logical but may be subject to sudden changes (possibly of jobs) - you may easily get bored with the routine of work, so you need a job which is challenging, has lots of variation and keeps you thinking. You would probably be most happy if you have a position of some responsibility because it allow you more scope for self expression. (though your subordinates may necessarily see this as a good thing).
Have a look for the position of Uranus, and Saturn (traditional ruler of Aquarius), which may give you more information about yourself as an employee.