1. Ask yourself why you want to do a startup in the first place - whatever is the motivation, use it to overcome any fears you might have.

2. Ask yourself what is the worst that can happen... It is easy to launch a business, but the cold reality is that the odds of success are stacked against you and only a small percentage of startups become successful businesses...BUT 100% of business founders gain valuable experience regardless of the outcome - this is the upside in all cases. So if you protect yourself from downside risk (ie. don't put $500k to start your first company, keep your day job until the business is generating cash flow, test demand before building a product, etc.) then you can't fail.

3. Don't overthink and just go - since there are so many uncontrollable things that can and will go wrong you have to be almost delusional in your confidence that things will work out. The best time to get over the hump "of what could go wrong" is to start when you get the inspiration and just go. Some of the most successful entrepreneurs I know, don't overthink things...they just keep putting one foot in front of the next. I have one friend who has built several successful businesses and I am certain he could build a an office tower with toothpicks simply by piling one after the other and being patient.

All the best!