1) Allowing belief to overwhelm your Startup idea
Owning a business is not for the weak-hearted. The day-in and day-out workload of starting up can be monstrous as compared to any kind of laborious hard work you have done before. So do not bow out and try desperately to get over the enamored and extravagant idea of your startup that you had in your mind and try to grind out a practical business model.
2) Giving in to what customers propose instead of the spreadsheets
Your idea might pull substantial demand and render you into relying solely on what the customer has to say. This might work most of the time, for some specific startup ideas. But if your idea does not belong to this specific list, the only thing you should trust are the spreadsheets. Make sure your plan is feasible.Do the math, guarentee that the demand is tantamount to the sale and then move on. Customers are capricious, they might change any time.
3) Risking a family’s property or retirement fund
Your family would always want the best for you. Do not get carried away if you ask them to fund you by selling a property or something and they nod without a seconds hesitation. They might be irrational while doing this because they would trust you and your idea blindly but you should make sure that you yourself are rational as you are the one who knows the startup inside out. If you think the property/funding is worth more than your startup, look for alternative sources.
4) Miscalculating the time needed to launch
You might be too excited to get it all started. You might just want to launch the idea and be all curious about what the people have to say about your idea. But do not get overwhelmed by this excitement. Do keep a buffer zone of about 10 to 15 days before you finally present the idea to the masses. You would lose nothing and gain 10 extras days which would not hurt. You will definitely open up on time and have ample time to go thoroughly through everything again.
5) Equating personal experience with business expertise
Being a good cook would not guarantee a successful restaurant. Being a good mechanic would not guarantee an up and running workshop. Running a startup or business and being expert in what your business has to offer are totally different things. Committing this logical fallacy can hurt so be cautious.