If I could go back in time and give a younger me one piece of advice when starting my company, it would be - don't start a business, build a side project instead. Build it for fun, see where it goes, let curiosity be your carrot as opposed to the expectation of success being a stick.
Side projects are simple. In fact they're so simple that you work on them just for the fun of it. You get deep into it, with no expectations, let what you learn evolve what you do next and let the project basically pull itself out of you.
When you start a business there is an expectation of success attached to it, otherwise the business is a failure. You need to find a business model, figure out what your vision is and what the market size is. "Is it a big enough idea?" is often the question asked by friends, parents and investors. There's nothing more demotivating than talking about your business to a cynical aunt.
Secondly, you need to be able to sell your ideas to those around you, and do it without fear. The best way to shed the fear of appearing foolish is to actually do something foolish for the fun of it. Strangely, you'll find that everyone around you is a lot more encouraging in this scenario than if you set out claiming you're going to build a big business.
Big things are accomplished by the compounding effect of many foolish little things done over a long time. If you start off trying to do a big thing, you'll always feel unaccomplished because you're too focused on what you haven't achieved yet. Focus on the small things, work on little projects, make an app for your friends as a joke, file your aunt's taxes, write a blog, build a shitty robot. Keep doing that and just enjoy the process of building and creating things, and keep that child-like sense of curiosity alive.
The main reason for this is that you need to do the groundwork to prepare yourself to be receptive to opportunities when they come up. You never know when they will, but unless you are knee deep in something you love already, you just won't notice it.
“You want to know how to paint a perfect painting? It's easy. Make yourself perfect and then just paint naturally.”
― Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance