Learn when to break the rules and when to follow them. Generally, you follow the rules, but not always.
In many industries and organizations, there are general guidelines, rules, or ways of doing things. You may learn, early on, that generally, for example, employees should have one manager only or that you should never divide your forces in the face of a larger force.
Great victories and advantages, however, lie in consciously not following these rules.
For start up companies, your advantages over larger companies come from nimbleness and low costs. When you start your business, you are the technician, the manager, and the owner. You wear all the hats.
You will hire employees, and they will begin to take some of those hats.
Do not, however, force your people and processes under principles that slow you down or increase your costs.
As you scale, you will reach higher level nodes where payroll will increase. As you do this, profitability may decrease as you take on more people, but then it will improve as you improve and grow at that node.
Move fast and move cheap. Know when to break the rules and knowingly break them for the good of your business (when it makes sense).