I know what you mean. I have a strong preference for first person. But some stories simply can't be made to work any way but in third.
I wouldn't normally recommend a 'How to Write...' type of book because there is no substitute for throwing down words. That said, there is one that I did find helpful. Writer's Digest Books "Characters, Emotions, and Viewpoint" by Nancy Kress addresses the 1st and 3rd POVs. By helpful, I mean it made me think about the process of writing in these POVs. It is not a tips and tricks book, but rather shows illustrative examples with discussion of what works and doesn't. BTW, Nancy Kress is a successful science fiction author with many excellent novels and short stories to her credit.
There's no trick to it, you just need to practice - a lot - until it becomes easy. That brick wall you're hitting is actually a rut you've found yourself comfortably slipping into. Experimenting with other writing styles will help you get out of it.
You'll find, with practice, that you already have the skills to write in third person - it's almost impossible to write in first person without them (unless you have no other characters in your stories!)
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Why not read some stories instead
NEW! Want a quick read for your coffee break? Why not try this... Flash Erotica: Scrubber I must say it is an unusual problem to have, but that doesn't make it any less of a problem. Most of what we read is in the third person. News reports, magazine articles. He did this, she does that, the government will do the other.
I presume what you're saying is that you naturally write about yourself. Is that right? I don't really want to offer advice until I know exactly what you are doing. But if you'd like to explain it to me I would be happy to help.
I hate writing about myself.
If you read my stories you'll see I like (for lack of a better term) being the main character. It helps me give her (usually) a personality and make it more 'real'
You know, I don't even think about it. For erotica, I generally write first person (since I'm often riffing off my own fantasies) but I have written third as well. For me, it's just adjusting my imagination to be a viewer of the scene rather than an actor in it. Not sure if that helps, but that's basically how I handle it mentally.
As an author who has written in both formats, I find it depends on what I want my audience to know. Let me try to explain. In first person, I try to keep the information limited to just what the narrating character knows. But, if I want to give a hint or a clue of things, a bit of foreshadowing if you will, then I do 3rd person. Now, if you're not comfortable in writing 3rd person, then that's fine. My first attempt at 1st person was scary as I was only taught 3rd, but found a level of enjoyment in it. With 3rd, it allows me, the author, to not always focus on one character. Plus, as a female writer, I don't feel comfortable writing as a man would speak. I feel I would insult men by feminizing a man in 1st person so when I make my main character a male, I make the story 3rd person. I find it opens me up for more interesting stories. My first try was a challenge, but I found a moderate level of success from it. I've since written a few more and my latest won me a Recommended Read.
Write with what you are comfortable with. Experiment. Try different things. Maybe you first 3rd person story will be a HUGE hit!