guest posts are usually harder to get because the quality of the content has to be better.
like the person said a lot of sites charge for guest posts which makes them into sponsored posts.
the best way to get real guest posts is to find websites in your niche and contact the people who are writing the blogs.
This may take some research for example you can use Hunter to find hidden emails on sites
Hunter is the leading solution to find and verify professional email addresses. Start using Hunter and connect with the people that matter for your business.
hunter.io
This way you can get right to the people who are in charge of writing blog posts or publishing them.
You may also want to type the authors names into Google and see if they have a website or twitter that you can contact them on.
If they are writing for one website in your niche - there is a good chance they write for similar websites too, so this can roll into multiple guest posts from an author the websites trust and know.
Another tip to keep in mind is journalists are always looking for an angle, and if they are writing about your niche they need quotes or information to help them write their story.
Search for
#prrequests
#journorequests
on twitter and you may find something interesting.