What I do with the Aztecs that generally works like a charm is take Liberty until I get my free Settler and Worker, then take the right side of Honor (the culture duplication from barbs with Aztec/Honor opener is awesome). I will build mostly Jags and try to Rex to 4-5 cities. Barb hunt like crazy and head for Ironworking A.S.A.P. With about 6 Jags, and hopefully some iron to upgrade them, I can usually take out my nearest neighbor (usually a few archers thrown in as well). After that it's smooth sailing. I connect my luxuries, garrison my troops for happiness, build up my cities with floating gardens and play the diplomat with all my resources for a while. I then have the ability to choose whether to go for domination or space race.
What speed/difficulty/mapsize and type are you playing?
I thought the first three liberty policies kind of pointless for most maps/difficulties? Increased settler speed and increased speed of workers doesn't seem like a policy that will matter for the majority of the game, tho it will provide a boost early on, but there seem better boosts to take? The first liberty is good, but only after you have a few cities built, before that it's giving you only +1 culture for your capital, a poor choice for a first policy imo, not much bang for your buck and won't greatly speed up the time to your next policy.
Taking the first honor tree seems vital with the aztecs, the ability to locate newly spawned barb camps, increased combat bonus against barbs and a whopping amount of culture for every barb killed seems like the better choice over the first liberty policy which will only give you +1 culture per turn per city (likely only have one city at this point).
Next policy you would take is a free settler or worker? If you're looking to pull off a rush (assuming a close neighbour) then wouldn't it be better to grab the next honour tree policy, gain a great general and increased speed in producing melee units (jaguars), since producing melee units is what your city should/will be doing at this stage, to maximize barbarian hunting and prepare for the swordsman upgrade.
I'm not saying having an extra worker or settler isn't helpful, but it seems like for higher difficulties that is going to extremely impede the speed with which you can field an effective army capable of taking a close neighbour out. With 4-5 cities you'll be slowing your ability to get quick policies and maximize military benefits of the honour tree as well as forcing you to build happiness buildings, go for happiness/money techs and build more workers to deal with your many cities, as opposed to what you should be doing in beelining ironworking, building a bunch of jaguars and using them to hunt barbs for mass culture and rapid honour tree exploitation.
I generally find 3 cities to be the magic number on pangaea or continents standard size map normal speed. I'll often have the majority of my conquering forces built before I even build my second city and that second city is often a settler I buy with barb/citystate/artifact/open borders gold just to get Iron. It allows a very early rush with highly upgraded troops with 10% near adjacent unit, a great general and 50% quicker experience. I'll buy my third settler for my third city soon after crushing my first enemy, with the gold I get from them.
This worked consistently on Emperor and thus far in my recent Immortal game it has proved just as useful. Plus, unlike the Liberty tree settler and worker policies, these honour tree policies will be useful throughout the entire game in the one area of the game in which the human player has an edge and a chance of using that edge to come out ahead - the military. The only liberty tree I might get is the very first one, but only AFTER I've conquered a sizeable amount of cities which will cause the +1 culture per city to be powerful. Really I try to avoid liberty and tradition for domination games, focusing exclusively upon honour and patronage (patronage is amazing).
Also, is there really no diplomatic penalty for abusing the trading system? I haven't seen it mentioned on these forums tho I'm sure others do this as well: You are prepared for declaring war on an enemy, your troops are all arranged and ready to move. You open a diplomatic screen with your intended victim and ask them what they want for all of their lump-sum gold on hand. They ask for every resource, luxury and strategic you have, you agree, you close the diplomatic screen after having gotten between 200 - 500 gold (I'm not sure whether it's necessary to close the diplomatic screen but I do just in case). You reopen the diplomatic screen with the same civ and declare war, cutting off the flow of resources before the ai has benefitted from them and you meanwhile still get to keep the gold. This is also something which is useful to do against civs on the other side of the map whose army you dont have to fear.