» Don’t ever think you’ve got everything figured out. Life is full of surprises, and business is more so. Be prepared for the unexpected by always having a Plan B (or even a Plan C) in place.

» Don’t assume anything (see also Nos. 11-15). Talk to people so that you both understand and agree on whatever you are discussing. As it was said by Samuel Goldwyn, “Oral agreements aren’t worth the paper they’re written on.” Put important agreements in writing. If people are offended when you ask that it be in writing, you probably are better off not doing business with them.

» Don’t accept responsibility without the associated authority. Without the authority to command results, you will be able to complete your responsibilities only with a lot of difficulty — if at all.

» Don’t believe everything you hear. Unless your source is proven reliable by long experience, verify and double-check promises and agreements. Make reminder calls when appropriate. (It’s appalling how often other people forget their commitments.) And don’t forget yours.

» Don’t ignore your competition; they won’t forget you. Check their prices, strategies, products, etc., on a regular basis. Do periodic — and anonymous — checks on their prices, their promised delivery, how they operate and other important operational matters.

» Don’t neglect to use a financial “road map.” Reading financial statements is tedious for most people but vital to tell you how you are doing.

» Don’t depend on just one source for whatever you buy. If you have only one supplier, what will you do if he burns down over the weekend?

» Don’t ignore the possibility of doing work in your own facility that you would ordinarily “farm out.” It is comforting to know that you can do the job “in house” in case your regular supplier fails you in some way. Conversely, if you are doing some work in house, try to locate an alternate outside source — in case you have a fire.

» Don’t neglect important suppliers or vendors. Pay them promptly. This will make you an important customer and will pay off with various concessions from them or when you need a favor someday.

» Don’t ignore good advice. Learn to discern good advice from bad advice (not easy to do but worth the effort).

» Don’t assume that there are venture capitalists or “angels” out there who will invest in your “greatest idea since the invention of scented toilet paper.”

» Don’t assume that you will have enough time to get everything done according to your schedule. Everything takes three times longer than you predict and costs twice as much.

» Don’t think that there are government grants out there that will get you started. There are grants out there, but your chances of getting one are slim to none.

» Don’t assume that expenses don’t count because you can “write them off.” You have to be making money to be able to write off stuff — and even then you don’t really want to.

» Don’t assume that you will be profitable after a month or after six months — or perhaps not even after a year. Plan to have enough money to live on separate from what you expect the business will generate.

— Paul Burri is an entrepreneur, inventor, columnist, engineer, guerrilla marketer and iconoclast. He is available to local organizations for speaking engagements and to local businesses for business consulting and/or mentoring. The opinions and comments in this column are his alone and do not reflect the opinions or policies of any outside organization. He can be reached at pburri@cox.net. Click here for previous Paul Burri columns. Follow Paul Burri on Twitter: @BronxPaul.