This probably isn't the answer you want to hear but I found my first clients on Upwork, I had a few screenshot's of fictitious apps and home pages I'd created and they were enough to land my first few projects. My first 2 clients actually approached me which was really surprising.
In terms of proposals I try to send quality over quantity. I see tons of people applying for projects and their skill-sets don't match up with the project they are applying for. I think lot's of people on there apply with cut and paste proposals rather than spending time writing something unique and actually applicable to the project they are applying for. Also when your write out a nice proposal keep a copy of it saved in Evernote so you can tweak it and re-use it again. Rather than just talking about yourself and why your the best for the job ask them more questions about the project as it show's you have an actual interest in it.
This probably isn't the answer you want to hear but I found my first clients on Upwork, I had a few screenshot's of fictitious apps and home pages I'd created and they were enough to land my first few projects. My first 2 clients actually approached me which was really surprising.
In terms of proposals I try to send quality over quantity. I see tons of people applying for projects and their skill-sets don't match up with the project they are applying for. I think lot's of people on there apply with cut and paste proposals rather than spending time writing something unique and actually applicable to the project they are applying for. Also when your write out a nice proposal keep a copy of it saved in Evernote so you can tweak it and re-use it again. Rather than just talking about yourself and why your the best for the job ask them more questions about the project as it show's you have an actual interest in it.
That's what has worked for me anyway :)