You need to create a sense of trust with your target audience when building a business so they will actually buy your products. To build that trust, you need to demonstrate your credibility and that you have the required expertise. Lack of expertise is a major reason people don't act on starting their online business. But the Internet makes it really easy to become an industry expert and to start selling products people want.

Run Your Own Blog: If you look around, you'll notice that a majority of experts in various niches maintain their authority by running their own blog, so what's stopping you? When you have your own blog, this becomes your online mouthpiece and it shows the whole world what you know. Your blog gives you a chance to show your readers what you know and what kind of content you produce. Since your blog can be accessed by anyone for free, it shows the world that you're willing to give things away and aren't just trying to sell something. Your whole objective with having a blog is to create an authority and have people trust you. It also gives you a platform to interact with your readers and get to know what's on their mind.

Having a blog is essential for anyone who wants to build expertise in any area.

Seek Joint Ventures: There's no better or quicker way to become an authority in your niche. Let's face it; there are already established experts in the market that are trusted by their target market and know exactly how to go about everything. Why not take advantage of their reputation by becoming their partner? The idea is to partner with this person to build your own reputation, so you also have to think of an advantage that the expert can gain from this partnership.

Become Known As an Expert Speaker: If you search for live events within your chosen niche, you'll probably be able to find some in your area where you can speak. Some events will allow you to simply sign up as a speaker, while others will require you to contact the presenters ahead of time. You can start off with small scale events where there's a demand for speakers who have something to offer without being paid. This is beneficial for both parties, as you have a chance to gain publicity while the event is getting a free speaker.

Just make up your mind that you're going to be seen as an expert in your field one day, and if you work at it steadily that day doesn't have to be very far off.

Resources:
my online income
Easy Steps That Will Make You an Expert in Any Niche
Become an Industry Expert in Your Niche Overnight
Effective Ways to Get Backlinks From Other Blogs
How to Be Known as an Expert in Your Field
Essential Factors of List Building for Your Online Business