If i find a niche that has more than enough room to grow, and this niche involves selling an ebook, would it be legal to buy my future competitors ebook, study it, make one similar to it, and just make it a little better. Is there any risk involved in this sort of thing? I dont want to do anything illegal or be accused of plagiarism.
There is a possibility of copyright infringement depending on exactly what you are planning on doing. I would suggest reading the copyright sticky at the top of this thread. It would likely be a lot safer if you didn't buy the book and then try to "recreate" it but rather produced your own book without their input.
My suggestion is to learn a lot [from books] and then practice it and then write your ebook based on your experiences and what you have learned. Everybody has to learn from somewhere, but don't just create a duplicate or a semi-duplicate, do it your way..
You should really follow what lightless said then write a few drafts to see what you come up with. Sometimes the act of writing the same stuff a few times can trigger a little creativity. Even if its really hard work the results will be better in the end. And probably the final product will have more of your own style injected in it. So write a draft, then a draft using previous draft on so on.. Untill you get a product you are happy with. Then compare with other sources to check if it looks original.