[Q] For Web/App Developers/Marketers here - Best way to find clients?

Hello to all

I have question for all developers or re-sellers here - what is in your business-life best way to attract leads and clients regarding Web/App Development?

I really can not catch up with all - with new techs in development and SMM for example or any other marketing forms. So, I will really appreciate some good advice how to market (where) my services?

Thank you.