The swish pattern is probably the most well known technique. To get better results with it, try not just visualizing, but hearing the sounds, feeling the feelings and movements with what you're imagining. A common mantra when being guided through this is "imagine, sense, and feel."
It can be difficult to lead yourself through the NLP techniques. Accessing your subconscious mind and trying to consciously lead it in the direction you want to go is...tricky. A simple way to fix this is to get a digital voice recorder. Start with a relaxation pattern, like a Dave Elman, then follow it with whichever NLP technique you'd like to do and finish it by counting yourself up.
Here's a technique that works well for me. It doesn't require a relaxed state and it's active, which is fun. It's the circle of excellence combined with and altered version of the hammer technique.
1) Choose the state you want. (ex. confidence)
2) Think of a time you experienced this state.
3) Imagine a circle on the ground in front of you. You can make it look anyway you want, use any audio cue you want, etc.
4) Recall your desired state from step 1 and step into the circle. Fully associate with that state and step into the circle.
5) See the time that you felt that state and really imagine, sense, and feel not only what is happening around you, but what is happening within you as well.
6) Amplify your state by enriching your submodalities. (ex. make it brighter, make your inner voice more compelling, make images bigger, etc.)
7) When your state is at its highest point create and anchor. ( ex. make a fist or press your pointer finger and thumb together)
8) Step out of the circle and break state. (an easy way to break state is look up, look down, look left, look right, and say your favorite color.)
9) Test it, see how easy it is to recall the state by simply stepping back into the circle or just try firing off your anchor.
10) repeat the process until it becomes easy to access your desired state.
Once it's easy to call up the state:
1) put your hands out in front of you.
2) Imagine yourself standing in one hand and imagine your favorite animal in the other.
3) Look at the image of yourself and get a sense of all the things that make you great.
4) Look at the image of your favorite animal and get a sense of all the things that make that animal great. (ex. is it powerful, graceful, dominant, etc.)
5)Bring your hands together, smashing the images together and bring you hands and the images to your chest. (actually touch your chest)
6) when your hands touch your chest, say a word that pumps you up. ( I like to use "Shazam")
7) Repeat this three times.

When I start my night at a club and am just beginning to approach, I find it helps to visualize my circle on the floor in front of me, so I walk through it on my way to the group I am approaching, and fire my anchor as I pass through it, and BAMPH! I'm feeling confident and chill by the time I grin and open.
hope this helps.