• Don’t say you know some technology/methodology/technique/whatever if you don’t. Most likely you’ll be checked.
• Chances are good that you’ll be asked to judge your knowledge in some area in some scale. Be skeptical about your skills because on the other side probably you have the best developer/project manager/sales/whoever in the team, not the average one. Your judgment will be compared to her knowledge. And if you gave yourself 80% and failed to answer majority of questions you’ll be marked as liar (or with overrated self-esteem what isn’t good either).
• If you don’t know something, say it. It’s far better than guessing and telling you know that for sure.
• If you don’t know something but have a clue, say it. Often good reasoning is as good as knowing right answer and you still are considered as honest, because you said you had only a clue and wasn’t sure.
There is a fantastic method not to be caught on lying. Don’t lie.