Find some big brands that you love and investigate to see if they have used influencers in the past.

This is quite easy to see - simply go to that brand's Facebook page and check their posts and the hashtags that they use. Then do a search for those hashtags - if you see a lot of people using those hashtags and promoting their brand chances are good that they are influencers.

Check to see if those posts you find include sponsored hashtags. Influencers are required to disclose that those posts are sponsored using #sponsored or #paid.

Start sharing those companies posts and creating your own unique posts using the hashtags that the companies are using in their campaigns.

When you share a company's post or when you create a post sharing anything about a company tag them and use their hashtags.

Essentially you are being an online influencer for free for them - they will notice you and other companies will too!