Modern humans (in form at least) have several major advantages over dinosaurs. Humans are warm-blooded endurance hunters with much greater intellect than dinosaurs, and they breed like flies in comparison. In our own world history humans have hunted anything and everything that can be either a threat or a source of food... including other humans. We are so damned good at it that there are a lot of species that aren't around anymore as a direct result of us finding them either tasty or too dangerous to live next to. Humans with weapons made of wood, bone and bits of stone killed off a number of big, nasty animals.
The same will be true of the dinosaurids of Aztlan.
The template cultures for your humans are largely warrior cultures who value personal bravery and such very highly. Individuals will likely hunt dangerous beasts to prove their worth as warriors as a rite of passage. The most respected and powerful warriors will likely have necklaces made from the teeth of the most fearsome carnivores they can find. T-Rex teeth would make fine trophies.
Recent research suggests that dinosaurs may have been mesotherms, so the old "wait until it gets cold and catch it while it can't move" methods probably aren't going to be entirely effective. You'll need some more direct methods.
Every human civilization at some point has figured out that having a long stick with a pointy bit on one end is a great way to hurt something without it being able to get close enough to hurt you. And every single one of those figured out that if you could throw the pointy stick you could get a little more time to run or prepare your next defense. Spears (Aztec: tepoztopilli), javelins and so on are staples of every early human hunting group. Refinements of these - like spears with a cross-brace to catch a charging boar - were still common up until recent times, and spears are still used by some enthusiasts to hunt with.
The next step up is using some mechanism to help you throw those spears further. Spear throwers - Atlatl, Woomera and so on - are common until bows (Aztec: tlahuitolli) are invented. They give advantages like being able to strike at an enemy from a place of safety. Stand on top of a cliff and rain death down on a creature below you and you don't have to worry about the thing fighting back much.
Of course you can also use something very much like a spear thrower to throw stones. Or just go with the good old sling (tematlatl), which is also remarkably common. Medieval slingers could take out cavalry units by killing the horses with rocks to the head from a hundred yards. Or perhaps worse, breaking their legs.
Apart from the atlatl, another South American classic is the Bola. Might be a bit harder to swing one that is big enough to inconvenience a T-Rex, but you'd be surprised at how effective these buggers can be. Not just for tripping things up, the spinning ends of the bola accelerate as the cords wrap around an object, and when they finally hit the flesh they can break bones. Add spikes for some extra nastiness.
What Else Though?
I'd be willing to put a man armed with a long, sharp knife and years of hunting experience up against a T-Rex if he was prepared and ready to hunt it. It might take days to wear it down but eventually the man is going to get the better of it.
Thing is, humans are damned tough to stop. We have good enough senses that something the size of a T-Rex isn't going to sneak up on us. We can hear them breathing from a long way away even when they're trying to be quiet, and those things positively reek to a human nose. We can dodge quicker than they can turn, and once you know about the tail whip you're pretty much just in an endurance competition.
And just about nothing alive wins endurance competitions against humans.
If the T-Rex tries to give up the hunter will circle around and come at it again. And again. And agains. By the time the kill comes the T-Rex will be collapsed on the ground without the energy to keep going.
The moral of the story is: don't underestimate humans. We're about the most dangerous thing there is... in the long run anyway.