I think it is better to just come up with your own content. Most of those type of programs that are designed to make things easier, really just make things more difficult. You are right. The more you write, the more practice you get, and the better you’ll become. I have been writing for years myself, and I have never needed any content generation programs.
For a blogger who has to publish multiple blogs on daily basis, it is tough for them to write unique content, especially when writing on same topics. In that case, spin bot tool could be used to avoid self-plagiarism and to maintain the quality on blog posts. As spinbot change synonym automatically but you can pick the most relevant synonym using out tool.