I have done the border crossing so many times that I learned to use some basic common sense rules:
1. Answer questions directly, but as vaguely as possible. For example: the question "What is the purpose of your visit?" should be answered, "weekend vacation." It's a direct answer, but vague and provides no info. My experience is that when you give question begging answers, they don't follow up and eventually you wear them out. If they follow up with a question like, "any particular plans?", I zap him with another question begging answer: "as soon as I check into the hotel I am going straight to the concierge and together we will make some plans." If you keep responding to questions with question begging answers you will wear the fuckers out and they will stop.
2. When they ask occupation questions, hit them quick and hard with detail. When this question comes up, I always get asked what kind of attorney I am. I hammer this fucking question with two sentences full of big legal words that the fuckers do not understand. 20 seconds later I see that glazed look of incomprehension and when I see that look, I know I have won and the questions are coming to an end.
3. Keep a polite, and humorous demeanor. This is a little easier on the US side, for language and cultural reasons. Chercherfemmes and I are both Americans so we will always talk about something we got away from that we were happy to get away from. If you can make the border guard laugh you throw him off his game.
4. On the way back, focus on one part of the trip that is not hobby related. The US border guards always want to know what I did during the weekend. On one trip back, I told the US border guard I went to the hockey game when I actually had only watched it on TV. I could tell the guard knew a bit about hockey, maybe not on the level of Joel Cairo, but on a high enough level where I had to throw out some stuff like "did you see when Parros dropped his gloves and the other goon pussied out", or some other detail from the game which will get him focused on one thing and again totally throw him off his game. As soon as he starts talking about the play I brought up, I have won, again.
5. If detained by Customs, do not panic. It happened once a long time ago and the Canadian customs agent kept asking me - I think he asked me 5 times- if I had a DUI. I kept telling him no. Then he said to me, in a grave voice, "I am going to run your passport in the computer and I hope you are telling me the truth because if you are not, you are going to be in trouble here!!!!!!!!" At this point I got pissed because I had been telling the truth about no DUIs, so I told a little fib. I whipped out my business card which IDs me as an attorney and told him if I had a DUI my license to practice law would have been suspended. This is not totally true - if I had a DUI conviction I could be presented for a suspension, but it's not automatic. After this the fucker calmed down with the condescension and intimidation.
6. Screen your travelling companions carefully. When I came to Canada for GG2 with a buddy I will call Phil (not his real name), Phil's friend, whom I will call Victor, was originally going to come with us. Victor told us he had a DUI so Phil and I told him he had to pay the Canadian consulate $300 for a DUI waiver or drive up in his own vehicle in case he got detained, because we were not going to get turned back because of him. We did not want to flat out reject him, so we gave him the choice between these two unsavory options. He said no to both choices, and stayed home. It's called paying for the consequences of one's actions. It's too bad but there was no way Phil and I should have our trip fucked up by Victor's screw up in the past which we had nothing to do with.