i've proven and ranked sites myself on top of serps in particular keywords.
how can i start providing SEO services to others?
garfish (27 August, 2010)
bogart is right, you'll need some sort of landing page on a site somewhere that shows what you offer. Then try getting ranked well for related phrases that will bring traffic to that page.
Create a nice website.. explain all your SEO services(link building, content writing, Press release, branding etc) there.. show few of your sites as example.. i would recommend atleast 3 sites ranging from low to moderately high competitve niche, if you can get tops SERPS in a highly competitve niche(dating, web hosting, weight loss, cancer) then great.
I have developed a website where people see my previous work and the websites, i have worked that better rank on search engines. An online portfolio is a nice step to attract the clients, and second option is as said by david-08 is to make profiles and bid on projects like freelancer.com, guru.com etc
I would say, launch a site for you and promote it and get clients for you. Simple