Portrait photography can be a challenging aspect of photography; capturing a photo that appears natural and conveys the subject's personality is a skill that for sure takes practice. But you don't need any fancy equipment to snap great portraits, portrait photography is about capturing a sense of a person's character, rather than producing technically perfect compositions. Portrait photography is all about people. Think about what makes your model so uniquely and try to capture that in your portrait.
A great way to get a natural looking portrait photo is to photograph the person when they're off guard or not posing. When you put most people in front of a camera they automatically put on their 'photo stance'. Shoot loads of photos. Shots are cheap, particularly when it comes to digital, so fire off as many as you can. Your relentless snapping will make it impossible for your model to keep up their posing, no matter how hard they try. and you'll likely get your most telling shots.
If you shoot a portrait photograph from too close, you will distort the subject's face, making it seem round and bulging, with a huge nose. This can be very distracting, not to mention completely unflattering. Move back as far as your lens will allow and zoom in on your subject. The further back you can get, the less distorted their face will be, and the more attractive and 'real' your portrait will look.
Lighting with additional gear as flashes or just with some reflectors can produce some great enhancements. But as I came by yesterday I didn't have ny fancy camera and neither any fancy flash gear. Which would have been as well not as unobrusive as I would have liked. Nevertheless I got a shot that I like.