In my opinion, it’s not the idea of playing against yourself as it is playing with yourself (get your mind out of the gutter)!
If you don’t want to just begin with a specified configuration, a solid strategy may be to just begin playing a couple of moves from normal openings and their well-known defenses. At this point, you may think, “What is the best path to go now?”
Since you are only about a couple of moves in, there’s a solid chance that you’ll get to a configuration that has been deeply studied and you’ll discover the best move from there by using a reliable source.
Now here is where it begins to get agonizing. As you go on, after each move you should question what is the best move going forward is, and then look at your dependable source. As you get going into middle-game it is reasonable that you reach a configuration you’ll have to return to an engine for the next best move.
You could very well have used an engine from the start. But for most openings, you’ll find the best potential moves for the first couple of moves explained with annotations on a website or in a book.
Another easy, hassle-free technique is to set up a configuration from either a good GM’s game or from one of the several chess books available and ask yourself, “Now what?”
Also, I believe that if you don’t have anyone else to play with, then this could be a good practice, but nothing beats an over-the-board experience with another human, particularly in a timed format. So, try to look for a chess club in your area. Even if you can’t do that, play online chess games. The main thing is to play. Nothing is better on a daily basis than a stimulation of the mind!