First things should come first. If you can afford an acting coach, it's a good idea to get one. There are many talented actors and actresses who spend their lives doing jobs other than acting. Hiring an acting coach to help hone your skills and teach you various methods of acting can be the difference between doing TV commercials and big budget movies. There's nothing wrong with TV commercials, but if you want to act, the movie business is where you eventually want to be. Finding an acting coach might be difficult, depending upon where you live. Check local papers, especially entertainment guides. You might even consider an online acting course (see resources). If you're serious, though, you will want to consider one of the hot spots such as L.A., New York City, or Atlanta. These cities have many talent agencies and it's easier to find an acting instructor.
A portfolio is an important step to becoming an actress. Your portfolio should contain professional photographs of you, both natural and glamorous. The photos should be 8X10s and a mix of color and black and white. You should also include a resume in your portfolio that details all the experience you've had in the acting world. The portfolio will be part of the package you use to market your talents to an agent who can get you work. In order to build acting credits, you will need to take the opportunity to act anywhere you can. These credits may not be big at first. It's hard to get an agent without having had some experience in the field, but getting experience in the field without an agent can be difficult. In the beginning, you will have to find every local opportunity you can to perform in plays, beauty pageants, and talent competitions. Anything you can use to build your portfolio will be helpful.