Do you have a portfolio already so people can see what you can do?
Do you have testimonials from previous clients that you worked for? If not, you need a different approach. You need references, you can make a free project to someone to prove you are good at, then, you ask this person for a testimonial, for demanding clients. Not all clients are demaind, but the good ones are.
Another option is to sell Wordpress premium templates, there are plenty of places for that, and there are lots of people making money this way, selling plugins, too. Themeforest is a good place to sell your templates that will also be used as your portfolio.
In this industry your best friend will be the Mr. never-stop-learning. In this industry, new things are coming out all the time, if you stop learning, you'll be left behind. Never stop learning; be curious, learn everything you can.
I'm this way, -- hungry and thirsty for knowledge.
If you want to succeed in this industry you have to be this way.
Web development is a big field, you don't have to be the best to succeed nor know everything(something that's kinda hard).
Promote yourself, create a good portfolio and the results will be along your way.