There are two ways to approach, direct and indirect.
Most newbies will start off with the indirect approach as it is safe and less intensive. However, as you get better with approaching, many PUA will recommend the direct approach. It cuts to the chase, saves you a lot of time and may get better result.
By approaching directly, she will see you as brave, confident and a masculine leader.
To approach directly, simply walk straight up to her and give her a compliment.
When walking up to her, stare right at her and smile. If she notices you walking towards her, she will perceive you as brave.