I had(have) the same problem but I'm successfully resolving it.
In the last 10 days I made more progress than 10 years combined before.
Why? Because I realized that the problem is inside of my mind.
What is causing me to not finish/doubt my own projects?
There are many reasons, each unique to each persons's mind.
One must brutaly focus in on the specific reasons and resolve them.
The solution that is working for me: sit in front of PC, close my eyes, focus on the problem.
I am NOT talking about regular meditation. You have people who mediate hours for their entire life and get nowhere.
What DOES work is to bring and hold the problem in your mind and just let it "hover" there. Eventualy you will start getting random thoughts/ideas which will show you details about this thing and your reactions to it that you have never seen before.
Note that this can take anywhere from 5 to 30 minutes. But very often I get many insights in a single 30 minutes session, many more than just one. But it's a bit random.
Basicaly it has to be active meditation.
I hold the problem in my mind and after 5, 15, 30...minuts solutions start popping in.
Listening to Jiddu Krishnamurti is what "pushed me over the edge" to realize that sitting down alone in a quite room and examine your mind is the only way forward.
Your problems will be specific to you.
In short, you need to figure out what is preventing you from monetizing and finishing your side projects.
This thing that is preventing you is in your mind.
You are uncertain. Uncertanty creates a "choice" in your mind.
You will then pick A over B, but because the uncertanty will still be there you will forever cycle between A and B, never commiting to each.
Address the source of the uncertanty. When you do that, the choice will dissapear and never bother you again.
The problem with this advice is that I cannot give you specific advice since you will have to figure out what is causing resistance in your mind against monetizing/commiting to your side projects.