What are your experiences and strategies for long-term investing?

Looking to minimize time managing investments. My plan is to make moves quarterly, aiming for 8-10% annual returns with consistent monthly contributions. Currently testing Dollar Cost Averaging (DCA) and Enhanced DCA with some early success. I mainly focus on ETFs and bonds, with a small portion for experimenting. I'm especially interested in insights from those with 10+ years of investing experience. Any tips or advice to share?