Are you trying to get others to guest post on your blog? Or are you wanting to place guest posts on the blogs of others?
Either way, you need to do your homework.
Find bloggers who regularly write about your target subject. If you want them to write a guest post for you, reach out to them and extend the invitation.
If you want to write a guest post for them, first check to see if they accept guest posts. Many do not, and will not necessary react kindly if think you are pestering them. If they publish submission guidelines for guest posters, follow the guidelines and instructions. You do not gain any points for being "creative." Rather, it will likely get your submission rejected. If they do not publish submission guidelines, but you see they have published guest posts before, it may be OK to reach out. Send them a polite proposal. Do not send them a complete article, or try to specify when or how they go about publishing it. That's pushy and rude.
If there are no submission guidelines and you don't see any guest posts, it's likely they do not accept guest posts. You can still approach with a politely worded pitch, but be prepared to be rejected the majority of the time.
And, of course, if they come right out and say they don't accept guest posts, you should respect that and avoid pitching them.
Whether you want them to write for you or you want them to publish your article, it's a good idea if you have actually read some articles on their blog. That way, you can be sure they really are writing about the topic you think they are. Do not assume you know what the blog is about based on the blog title.
I have a blog that includes the word "bootstrap" in its title -- as in "to pull oneself up by one's bootstraps", i.e. "do it yourself". I do not accept guest posts. There are no guest posts on the blog, and I have no submission guidelines posted. I cannot tell you how many unsolicited offers I've had for blog content related to shoes
, which has nothing
to do with the topic of the blog. Clueless "marketers" see the word "bootstrap" and assume it has something to do with footwear.
The main things are to try to target your requests as best you can to the people who would be most receptive, and don't take rejection personally. Because it will likely happen more often than you'd like.