Firstly you will need a website. I recommend to use Wordpress content management system or CMS for short. Once the website is created find a reputable search engine optimization company to get the website to rank high in Google so you can get organic search engine traffic to the site.
You can also use Pay Per Click advertising through Google adwords but I would be careful with this method. If it's not done correctly, you can lose money.
You can buy an ad spot in many used websites like Facebook, Google, Yahoo, Bing etc. If you have your business professionally made, they will usually do all that for you for a small monthly fee.
Do SEO, SMM, SEM for your business.