A good way to promote a company or brand is to advertise such as on the radio, in newspapers, online through advertisements such as Google Adwords, Buysellads etc.
Also you could go to Taboola and advertise your brand through Taboola, or through Facebook ads or Twitter Ads.
Promoting your brand through twitter is also a good free way of promoting your brand and others can tweet your brand out to other people.
Advertising on Youtube is also a good way to promote your brand quickly to interested people as well although it's not cheap.
But if you're selling things that can net you a good profit then advertising on Youtube video ads is a good way to get your brand noticed and fast.
There are billions of people on Youtube that watch ads on Youtube so you can get your brand noticed fast.
Another way is to pay a lot more money and run TV advertisements which work well because companies use them.
Just make sure you make a good advertisement that make people interested in your product or brand.