Let me guess … you walked into work this week innocently enough, and then, out of the blue, Bob from finance asked you to join the NCAA tournament pool and promised it would be loads of fun.

Now you’re staring at this 64-team grid, and you don’t want to embarrass yourself and look like a buffoon in front of your co-workers.

Don’t worry, I’m here to help. Today we’ll review some of the basic rules that lead to a good tournament bracket.

By a “good” bracket, I don’t necessarily mean “successful” — because of the tournament’s single-elimination format, random flukes can and do mess things up, which is why the person who knows the least about basketball often ends up winning the office pool. The idea, instead, is to give yourself a chance to win. Remember, if 50 people enter the pool, you only have a 2% chance of winning. Even if my genius quintuples your odds, you’ll still only win once a decade. Don’t say you weren’t warned.

That said, a few simple steps can greatly reduce the risk of catastrophe. And in some years, that could end up as the difference between finishing in the money and throwing away another $20.

So here goes:

You can’t win the pool in the first round: You should seriously consider taking all 32 of the higher-seeded teams in the first round. Your co-workers will undoubtedly mock your lack of spine, but stand firm — the only thing you can do in the first round is screw up the rest of your bracket for later.

Sure, it sounds great to say you picked Oral Roberts to pull a huge upset if it comes to pass that they actually win … but chances are they won’t. That’s why it’s called an upset, Einstein.

If, for appearances, you feel you absolutely must take a lower-seeded team, I can offer you a couple of decent options. First, in the West region, no. 9 Texas A&M has an outstanding chance of taking out no. 8 BYU in the West. Since no. 9s have played well historically, this is hardly a giant leap.

Second, there’s no. 10 St. Mary’s versus no. 7 Miami in the South. I mentioned on Monday that I felt Miami was overseeded, and our Jonah Keri echoed my thoughts when he tabbed St. Mary’s as a likely first-round surprise. The Gaels appear to be the superior team statistically, and Miami finished the year 8–9 — with six of the losses coming to teams that didn’t make the tournament.

Survive the first weekend first: Just because there are a bunch of second-round upsets every year doesn’t mean you have to try to pick them. Don’t attempt to guess which no. 1 or no. 2 seed will take a fall here — you’ll just end up being wrong twice when your predicted victim advances and another team takes the fall instead.

Instead, pencil every no. 1 and no. 2 seed into the Sweet 16. Now comes the hard part – the middle seeds. No. 3 seeds have a surprisingly poor track record in the second round, so finding a couple of vulnerable ones here isn’t a bad strategy.

As I mentioned on Monday, Marquette appears unusually strong for a no. 6 seed and makes for a great play over no. 3 Stanford in the South, so that’s one I’d recommend. The others don’t look as compelling this year, so go easy, cowboy — it’s fine if that’s you’re only no. 6 in the Sweet 16. As for the no. 5 versus no. 4 matchups, those are pretty much toss-ups historically, so feel free to be more creative here. Among no. 5 seeds, I especially like Clemson, whose likely opponent is a grossly overseeded Vanderbilt team. In the other three games I just shrug my shoulders.

Now, for the hard part: With 11 of the top 12 seeds joining Marquette in your Sweet 16, you’ll definitely survive the first weekend with a chance of winning your pool. Now, it’s winning time.

This is the part where I can help you the least, because most of these games are extremely competitive. However, no. 1 seeds have a strong track record of advancing to the regional final, so without overwhelming evidence to the contrary one should move the four top seeds to that line on the bracket.

That leaves four games to pick, and all are essentially toss-ups. At this point you have no. 6 Marquette versus no. 2 Texas in the South, and three no. 2 vs. no. 3 matchups in the other regions. What to do? I’ll tell you …

Go against the grain: It’s crazy to pick upsets early, but it’s smart to pick them late. One common element in most tournament pools is that the no. 1 seeds tend to be over-selected relative to their odds of winning, as are teams that just made deep tournament runs the year before.

The implication is that even if you pick those teams correctly, you can still lose because 10 other people did the same thing. Instead, the Sweet 16 and Elite Eight are a great time to go against conventional wisdom once or twice. You’re only counting on a few games turning your way to dramatically shift the odds in your favor. The implication this year would be to take Marquette over no. 2 Texas and again over no. 1 Memphis in the South region; as I mentioned Monday, those are the most beatable of the top 2 seeds. You might also take no. 3 Louisville over no. 2 Tennessee in the East — the Vols will be a popular pick since they were ranked no. 1 for a while.

Now you can stick your neck out … once: You don’t need to go crazy picking all the underdogs in the regional finals, but one well-selected upset can spring your bracket to the forefront, even if your other favorites disappoint. As you can tell, I’m on the Marquette bandwagon. Join me for the ride.

You can make other adjustments from here. Ideally, keep two no. 1 seeds in the Final Four: one no. 2 (I like Duke here), and one team a bit deeper (like Marquette). That has the best chance of keeping you alive the longest without risking the dreaded “I picked the Final Four right and still have no chance of winning” scenario that comes from taking all no. 1 seeds.

Finish with a flourish: Put one of your two no. 1 seeds in the Finals, but don’t be afraid to take a risk with the other one and to have that team winning the title — actually, it can greatly improve your odds of winning the pool.

For instance, on Monday I said I’d take three no. 1 seeds and Marquette in my Final Four, with Kansas over UCLA in the final. But in a pool, I’d never do that — too many other people will pick the same thing.

Instead, I’d be more inclined to choose Kansas as my runner-up, and then tap a strong no. 2 like Duke to take the whole enchilada. Yes, I just threw up in my mouth a little when I said that, but from an odds perspective, that really is a smart pick. And if tournament pools are about anything, they’re about turning the odds slightly more in your favor.

jhollinger@nysun.com