1. Good glass
In my years of shooting fashion portfolios, weddings and landscapes. I found a certain fondness for the 20mm, 50mm, 85mm and 70-200mm focal lengths. A typical portrait photographer will tell you good glass gets you great images. Portrait photographers tend to use prime lenses more often than zooms because of their optical performance. Don't get me wrong a good zoom is necessary if you shoot on the go event like weddings where there is no time to fiddle about with lenses.
I recommend a good mid telephoto like a 85mm or 105mm for portraits.
2. Understand light.
Light is the most important factor in photography. A photograph is simply a digital painting of light on the sensor forming a image. When starting out photography no one has the money to spend on fancy lights and modifiers.
But shooting at particular times of the day can certainly help keep those bright highlight and harsh shadows away. Getting up early and shooting in the morning or waiting for late afternoon is the way to go.
- Place the subject with their back to the sun or slightly angled 45 degrees to the either side of the subject.
- Place your subject next to a window and light them up with the natural light comping in though the window, and if the light is still too harsh use a scrim soften the light.
- Shade is your friend place your subject under the shade of a tree or a building to prevent raccoon eyes or squinting from the bright sunlight.
3. Perspective
Move around and find what you want to capture take the time to run around like a headless chicken you might look silly but don't worry it will pay off later when reviewing your images. Shoot from various angles you might surprise yourself. Composition helps tell the story, ask yourself what you want to capture and then find a way to convey the emotion through playing around with your composition. Contrary to point number one I play around with various focal lengths to show of the surroundings or cut it out.
The angle at which you shoot can have a significant effect on your images.
- Get high - The higher the angle you shoot from will reduce the body size of the model at the same time emphasizing the size of their head. Wide angle lenses can exaggerate this effect because of the distortion they provide.
- Get low - Lower angles give you the opposite effect distorting the legs making them seem longer and the subject look taller than they actually are.
4. Learn post processing
If you want to step up your work I would suggest investing in post processing software. Lightroom is one of the most popular among photographers, it is quite straight forward and easy to understand. Available here Adobe Photoshop Lightroom
5. Keep on shooting
Grab a friend and practice. I can not stress this enough going out there and practicing is a major factor in improving you skill. Experience is the best teacher stay commited and never become complacent.