Collected over the years and verified time and time again.

All Laws subject to change without notice. 

1.  Let the romance begin. Clients want to get started immediately on new projects or campaigns but have neglegted to establish a plan, budget or closing date. The reality is without a plan, budget or deadline there is no reality. 
2. Only two people can say "yes!" to an idea. - One is the client who signs the check.  The other is the customer who buys the product.  If the client likes the ads, they run once.  If the customers like them, they may run again.  Agencies, work very hard to ensure that the ads run at least once.   Many of ours have run often.
3. People play by their own rules. - The more you want them to play by yours, the more likely they are to cheat or just walk away from the game.  Proctor &Gamble’s version of this law is, "do not violate established habits and practices."  To apply this rule to your own affairs, try to reduce the complexity of your products & services, web pages, phone directory, and other corporate barriers to entry or in a word: k.i.s.s.
4. There are no unique situations worth fixing. – Focus your intellectual energies and budget on wide-spread customer problems. Ignore the occasional heard whines and whimpers, wants, needs, and exceptional cases.  Have “Sales” fix those problems. Ignore gripes about your advertising efforts.  If one or two cranks call up to complain about that in your face headline or to tell you should have done this or that, be happy that you're cutting through the clutter.  In fact, if no one ever complains about your ads, they are probably not very good.
5. We are all freelancers.  - We just freelance some places longer than others. Company CEO’s change jobs about as often as copywriters.  Very few people work for the same company for their entire lives.  Most of them are already dead. Figuratively at least.
6. V>P>C= Success - Perceived Value must be greater than Price, or there is no sale.  
   Price must be greater than Cost, or there is no company.
   Ignore this rule and you fail.
7. There is no minor league in advertising.  - Just because you've never done this before doesn't mean you get a price or sympathy break on creative, production, or media. Total strangers will compare your first ad ever to the work of your better-heeled competitors and judge your brand accordingly.  (see law 6) The good news is that no consumers will ever base their purchase decision on the size of your Ad agency.
8. Emotions rule.   - Individuals behave irrationally.  They hope they are acting in their own self-interest. They fear making a mistake.  They are often wrong.  The longer people "think about it" the less likely they are to act.  Your ads can list ten rational reasons why people should try your brand, but they only need one lousy excuse not to.  (a common excuse is, "what a lousy looking ad.") groups do behave rationally, though (i.e. Adam smith's "market forces prevail").  If 35% of your customers buy and 65% do not, it may be that those 65% share an emotional block.
9. People only buy things they are aware of.   - The ninth law appears to be a truism. It is not. Brand awareness is an elusive quality misunderstood by most advertisers.  Beginners especially are often discouraged when they run one ad or send one letter and nothing much happens. Two or three calls from then zilch. "see, advertising doesn't work!" awareness means you must equal or overcome people's awareness of brands other than yours.  There are two ways to do that: massive media tonnage and/or better ideas. We believe we have better ideas.
10. All the advertising in the world  cannot save a bad idea.   - A good first impression run nine times will do a much better job than a lousy first impression run ten times.  Spend something on creative &  production. However, Hollywood production values cannot save a bad idea either.