Htadus is exactly right. On lower levels, Alpha is often a good beeline since you can trade for many of the little tech you generally would bypass. heck..you may even still get Oracle fairly easy trading for those techs after Alpha.
Alpha for Monarchy is a pretty good trade as well, although you may need to put a turn into Monarchy first or a small tech or two into the deal. Speaking of which it is not uncommon to part tech something in expectation of trade..you are still saving turns.
And keep in mind Currency, which can and should often be on your beeline path after Alpha. Once you add gold to the equation things become even easier in trading. For one, gold helps you to evaluate trade deals and whether an AI is in the process of teching something you already have. On turn x, evaluate a trade deal comparing tech you have and techs you want. I forget the dialogue option, but click the one that makes them evaluate the trade and make an offer. Noet what they ask for and how much gold they throw in or ask you for. On turn y, evaluate the same trade and see if it changes - do they ask for more or give you less? Evaluating trades also helps you know how to hold off on making trades as well, especially on lower levels as you may keep your monopolies much longer and keep techs like Alpha away from the AI. On..say..Prince or NOble, there is no reason to rush a trade for IW if you really don't need it at the moment. You still may have plenty of little things to trade for with little things they don't have. Just keep evaluating those trades and if you see the AI is starting to tech something then consider pulling the trigger. Ofc, if you really just need X tech to make a strategy happen asap then go for it.
This approach is always valuable, and generally I'm looking to make gains in gold as well as tech. And certainly I will trade old small techs for bits of gold. You will start to get a feel for the value of these techs in gold, but it decreases over time and how many known AIs have that tech. I will sometimes just trade a small tech or whatever for x amount of gold even if it's not really what it is probably worth, simply as that AI will likely trade for it soon anyway. Get what you can when you can, in other words.
It is further important to note that what I'm talking about becomes even more important as you move up levels. The need to not only trade techs but to be prompt and discerning in analyzing and procuring these trades is key to advancing those levels and keeping pace in tech.
And gold is always important if you can grab chunks of it to keep your slider up to 100%. Also, keep track of when a wonder is built, or even if you finish one, and have currency. Incomplete wonders can produce a lot of "fail gold", so check the AIs stash of gold after a wonder is complete and you may find some have quite a lot to trade for. Do what you can to get that gold without, ofc, trading away techs you really don't want to at that time. (Note: speaking of fail gold, a common ploy among advanced players is to deliberately not complete wonders, but put bits of gold and OF hammers into them if they have bonuses on that wonder from resources or the Industrious trait. It is actually what makes Industrious such a powerful trait)
So yeah, in most cases, AIs will trade Iron Working to you once you have Alpha, and as you move up levels it's almost assured some AIs will have IW by that point or soon after. Iron and iron based units are not usually a concern for me though early on, as I don't use them much. However, certain powerful UUs like Praets and Gallic Warriors require the Tech and/or resources, so sometimes you may beeline IW yourself if you want to make the most of those units early. And, ofc, sometimes you simply don't have copper or horses nearby so you want iron for some advanced units. But ask yourself if you can get by without it until you trade for it - sometimes maybe you can't, but oftentimes you can. Same goes if you are dealing with lots of jungle - do you have enough good land to work with in the meantime?
As for Alpha, higher level players mention that can might be bypassed, because they are playing higher levels. The important thing is to setup trades. When you start hitting Immortal level, and maybe even Emperor, AIs will often get Alpha fairly quickly. In that case, it is often suggested to go for Aesthetics, which is a tech the AIs often ignore for a long time. Aesthetics makes for a good bargaining chip to pick up Alpha among other things, plus it is on the way to Lit>Music for the free Great Artist (golden age) and possibly The Great Library. However, generally on Monarch and below, Alpha beeline can be good move. (note: iso and semi-iso situations can call for completely different methods)
Bottom line, it is important to choose optimal tech paths based on your situation, and that should happen early in the game. As mentioned more the once, the early game is so important. As you move up levels, things become less and less forgiving in that regard.
Agree with Lymond's list of AI priority techs but on Prince I think normally you have to self-tech Maths as it opens up so much.
Yep, you are correct..and I did note that caveat in my comments above. Even on higher levels than Prince I sometimes self tech maths depending on the situation, or if Philosophical I don't have any problem using that first GS to bulb it if it suites my strategy for that game, such as getting those boosted chops to get out a bunch of HAs....or even an attempt at a CS sling.
(Or maybe I'm too
pusillanimous to whip an army to grab some from the neighbors
.)
:
ha..there's a very suitable bit of slang that can be read from that. I recommend you check out some Youtube Let's Plays from Absolute Zero if you really want to see slavery at work..and he's doing that on Deity. But yeah, sometimes you are going to use whipping fairly liberally to get that war going. Newer players tend to be rather timid doing so...
...I think the key thing you will gather from AZ is that you while your cap might take some whips, you generally let it take on the bulk of research effort (growth, scientists, cottages), while most other cities get fairly abused. That is the balance you create to keep things flowing - economy, expansion and conquest.