Founder, Revolutions Consulting, Building Startups through Training and Human Capacity Development Programs. HR Consultant, Writer, Speaker and Trainer.
The best way to startup will be to focus on networking effectively with the stakeholders/decision makers in the niche market. Build a relationship with them and demonstrate you are able to offer quality service.
Second is to do a survey on other recruiting firms offering similar services, gain clarity on their recruitment fees/rates and offer something lower than the market to gain a competitive edge.
Also ensure to have reviews of past client engagements posted on your website/social media handles that your niche market can see in order to establish reputation and trust.