Great pieces of advice

* Never lose goodwill: My Dad's always been a big proponent of goodwill. I usually am quick off the handle, but he's always stressed the importance of ensuring that any disagreements are handled such that at the end you can always shake hands and walk away without leaving a bad taste. I've tried to adopt this approach with clients, partners and employees, and it's turned out quite well. For instance, on one particular consulting assignment, things unfortunately got very heated up between us and the head of the department we were working with. But later that day, I went around and apologized, and he was more than willing to apologize as well. Today, we have a significant annual consulting contract with the same department.
* Never let the other guy lose face: This advice has come from quite a few people. During any negotiation or discussion, make sure you don't let the other guy lose face. Even if you win the argument, make sure the other guy doesn't come across looking like a sore loser. No one likes to be pushed against the wall, and in any situation she/he must be allowed to save face.
* Get a hang of the financial numbers: My background has been in technology. But poring over balance sheets, income tax rules, and listening to my accountant discuss depreciation, has forced me to get pretty interested in the financial side of things. Now, I have monthly key parameter reports which give me important numbers such as salaries, fixed expenses, domestic and overseas revenues, cash withdrawn, bank account balances, Internet/mobile/phone/electricity expenses, etc. A general idea of the main rules of taxation and accounting is extremely important when making operational and strategic decisions.
* Never sell yourself short (Sabeer Bhatia): Yup, that's the dude who sold Hotmail to Microsoft for a neat $400 million. I happened to meet him at one of the rare parties I was at, and went up to him and asked him if he had any advice given I had just started. And that's what he said. Initially, of course, when we didn't have too many options it's difficult to put a very high price on oneself. But we've always avoided going in for low-priced projects, and rejected a couple of pretty-tempting buyout offers along the way as well. In the consulting business, if one does not value one's own time and skills highly, then surely the clients can't be expected to do so.
* Increase your expenses: This is the one where I violently disagree with my Dad. His is the pure consumerist approach. Spend now, increase your expenses, increase the pressure to earn more revenues. Mine is the more conservative response: "Dad, I need to see those reserves in my bank, to be able to sleep well at night!". To which, he will usually say, "You should have the confidence in your future earning abilities to not need 6 months' expenses lying idle in your account".
* Trust your people (Ricardo Semler): The idea that a company can and should be run as a democracy comes from Ricardo Semler's ground-breaking book, "The Maverick". There are no policies, people set their own time to come and go, they are forced to take vacations, the pyramid is a circle, people set their own salaries, and other crazy stuff! As an entrepreneur, the toughest challenge is letting go - letting go of one's own responsibilities and allowing people to flower and learn from their mistakes.
* Look for people with energy and maturity (Jack Welch): As a consulting company, our valuation comes from the people that work with us. To be able to hire the right talent and attitude among the multitude of applicants, is a skill I am still learning. But Welch, in his book Winning, specifies these two attributes - energy and maturity - as being very important to look out for in potential leaders. Maturity is specially important when the consultant finds himself in a spot of bother on a given project, and needs to handle a delicate situation or reassure a frazzled client.

Feel free to add advice you've received, which has worked for you. There's also a lot of really bad advice we received, and I'll probably post on that as well!