Each time I want to start a business, I feel excited in the beginning but when I think about sales, I feel overwhelmed and I bail out I'm a software engineer with full time job, I identify a business opportunity, I do all the planning, I create business model canvas / plan in few days, I do all the planning following lean approach , set a schedule etc. I know my ideal customer and market, briefly all the theory is done, but when it comes to taking actions, talking to people and get some clients on the phone, I feel overwhelmed, and afraid to get out of my comfort zone I end up dropping the ball quickly and the idea falls in the cracks.
First of all, you are not alone! Almost anyone with a successful business has left a trail of half-finished ideas and projects. Sometimes we realize we don't have the skills to execute our ideas, or we don't have the capital, the resources, whatever.
Your question makes me think it's not that you don't have the skills to execute your ideas, rather it's that you run out of steam or get nervous. If this is the case, you might need an accountability buddy - someone who will meet you for coffee, listen to your ideas, and help you figure out how to make them happen.
My friend and I meet up once a month and update each other on projects on which we are working. I feel guilty when I don't have updates for her, and this motivates me to get stuff done. This is more of a mental hack for yourself, but it totally works!
You might also look for a Mastermind group in your area (or virtually) which can help you feel like you're part of a community and not going it alone. I've learned a lot from peers who are going through the same thing I am.
Happy to chat more if you want help thinking this through!