Being recognised as a professional in your niche will help make your internet marketing campaign more successful. If your name is recognized by people interested in your products and services they will be preconditioned to buy from you.
You should pick a product you have knowledge of. No matter how good your sales pitch, you will never be acknowledged as a professional if you do not have a genuine knowledge and interest in the product and service you are promoting. Having years of experience with selling or using a specific product can help, but you could also do a lot of research, take classes and read books and publications in your niche. If you are selling as an affiliate buy and test the products yourself. You need to know how the product is made and have a solid understanding of how it functions. You should also stay up to date with news and events related to your niche and make a contribution through forums or articles.
Write quality articles regularly. You need this regularity to build credibility. One off contributions generally have little value. Research all your articles and use reliable sources. Use only original and useful content: perhaps share ideas you have tested yourself, give a brief course on a specific topic or share your personal experiences. Publish images showing yourself testing and demonstrating products and consider creating your own videos or podcasts. Make sure you sign everything off. Set up a blog and post the latest information you have. Try guest writing for publications in your niche.
Develop a strong presence on social networks by using message boards, chat rooms and posts to build up a following. People should feel comfortable about contacting you with their questions and you should help them in a timely manner with quality advice. Do not push your products all the time but do your best to remain helpful, professional and polite. Make sure all your messages are signed off with a link to your website.
Develop your reputation in real life too. You could attend events where you get a chance to display your skills and talk about the things you know a lot about. Network as much as possible during these events, hand out business cards and do your best to dress and behave in a professional way. Get yourself featured in the media coverage of these events: do public presentations, record or film them and share them on the Internet.
Developing a reputation as a professional does take time, but your hard work will pay off. Work on your image, your writing and your content and always be helpful and polite. Like all business this is a long term process and persistence is key.