Here are a few of the lessons I've learned over the years.
In the end of your current venture, win or lose, be able to look everyone in the eyes.
Some days you will believe that you are invincible. Some days you will believe that you are hopeless. Know that these days are coming and just keep moving regardless.
My personal worst mistake ever was, when "fancy people" starting to pay attention and I was drawn to them, that I didn't bring my original people along with me. It wasn't on purpose - I was just intoxicated by the bigwigs that started to favor me. To this day I still feel bad.
Define and effectively communicate a clear vision. When everyone knows that you are travelling towards the brightest star in the sky then you will all arrive at the same place. You don't have to watch as closely if you already know very clearly where everyone will end up.
You can limit the "smarts" of your company to the capacity of your own brain or you can multiply the "smarts" of your company by the combination of everyone's brains put together. The only way to do this is with trust.
You can work the triangle in order to meet a deadline: time, resources, scope. By adding more time you can meet your schedule but it might be costly. You can add resources, like more people, but this can be expensive. You can reduce scope by cutting features from the product to get it done on time. HOWEVER, everyone forgets the power of motivation. Praise is free. Look for heroes doing heroic things and sing their praises. Let everyone know that you are on the watch for heroes. People like to be a hero and will work very hard to feel the pride of a founder admiring their efforts. A team that loves their work accomplishes more in a week than a team that dreads their work.
Empathize with your customer. Focus on the benefit you are offering to them. There is nothing wrong with a fair trade; their money for the value you provide them.
Remove barriers and get them out of the way for your customers. Make it quick and easy to understand the benefit you are providing to them. Make it simple to complete the transaction. Obvious benefit. Easy Purchase. Perfect.
When the sale is done your relationship with your customer is just beginning. Thank them (it's free!). Maybe give them an extra benefit that they didn't expect. Make friends with your customers by making them glad that they met you.
Remember your customer. Not just their name but more. Implement a CRM solution early on, even a simple one, so that each interaction is remembered. There is nothing more powerful than a customer who feels remembered and valued. Something like, "last time you called you were having trouble with XYZ and we helped you fix it - is everything still ok?". "How can we help you today?". Remembering the content of the last interaction is easy treasure.
We're all in this to make money but there's nothing wrong with being a good person while doing it. Remember all of the people, the one's who got you started, the one's who brought you to the next level, the customers, everyone. One time, when airline tickets were very cheap, I bought gift certificated for the families of every employee to thank them for sharing their loved ones with me for so many hours of their lives. It's so rewarding to build a family of good people achieving great things! Then, when times were hard, everyone stood shoulder to shoulder and worked their tails off the overcome the troubles. We were always there for each other.