Advice to make Let's Plays interesting?

Maybe don't do let's plays then but other content you might enjoy? How you feel about the game, features people might not know about, comparisons, background stories? But don't be discouraged by what you think your voice sounds like. Since you can't be the judge of that anyway (it'll always sound worse to you than it really is) there's no point in worrying about it. People will enjoy your content if you do, like @RiveniaSims said. So have fun with it and create whatever feels right to you. The rest will follow :)