I'm currently building my startup, and I see other companies having great copywriting, for instance basecamp, Dropbox etc.. Who does their copywriting? How do I find a good one? I have tried a few copywriters but it seems that I know it better then them. I like copywriting to be 'transparent', a little 'funky', with slight humor.
Create a "small copy-test".
"Our company is creating a new home page. Our goal is to optimize conversions. Write 'above-the-fold' copy you believe will optimize 'Start Trial' button click-throughs. Please complete within 96 hours."
Give this "small copy-test" to anyone you're considering to hire. Some agencies/freelancers/people will be offended Forget them. The people that know copy 'better than you' will not mind proving it if you have a good opportunity.
The key to a great copy-test is to keep it small and relevant.