One of the first things everybody wants when a new format is released is a pick order: some ranking of the cards such that, if you see your first pack and cross-reference it with said pick order, you know which card to take.
The ability to stray from this pick order is a great way to level up your game. You see, drafting is an optimization problem. You don't want the best individual cards. You want the best cohesive pile of cards, the best possible deck for your seat. Formats nowadays are very synergistic and archetype-driven, so a pile of good cards often isn't as good as you can get. And in order to really optimize your deck, you need to be able to treat your evaluation of cards with fluidity.
Every pack that you see provides you with a choice, and every card that you have taken previously affects that choice. Here are some tips for discerning when you should stray from your pick order.
Sometimes cards are much better in certain archetypes. Build-around cards are great examples. Riddleform is a card I'm quite high on, and I take it early in a draft because it has such a high ceiling. Yet in later packs, I will know if the card is good in my deck or not based on my archetype. Be aware of your archetype, and which cards are better or worse in it.
But as we all know, draft isn't always so clear-cut. Sometimes you're not entirely sure which archetype you're in. This doesn't mean that you can't use archetypes, and the probability you end up in a specific one, as logic to stray from your pick order.
In this draft I have placed my feet in blue and don't plan on moving. A fourth-pick Ifnir Deadlands is a pretty good signal, though, so I am looking to be U/B, but not tied down at all.
There are three cards to consider here: Farm // Market, Spellweaver Eternal, and Wall of Forgotten Pharaohs (note: that ordering would be my pick order to start). Funny enough, I think the correct pick here is Wall of Forgotten Pharaohs, and behind it is Spellweaver Eternal.
While I like Farm, I think that both Spellweaver and the Wall are both very good and have a higher chance of making my deck. Often you stray from your pick order to stay open!
You would think that, since I'm both blue and Spellweaver Eternal is higher than Wall of Forgotten Pharaohs in my pick order, the Eternal would be the pick. But once you consider the cards I've drafted, this changes.
I already have two Deserts, which gives the Wall a bump. Additionally, this Ifnir Deadlands means that the archetype I am most likely to end up in is U/B, especially since my other two cards are controlling. In this specific archetype, Wall of Forgotten Pharaohs is better than Spellweaver Eternal. The Wall is also better in U/G, which can even use the Ifnir Deadlands with enough cards like Oasis Ritualist and Manalith.
Once you consider the evaluation of these cards in different archetypes and combine that with the probability you end up in each archetype, you'll find that it is often correct to deviate from your pick order.
Filling a Hole
This is the easiest, but arguably the most important lesson. Save ridiculous bombs like the Gods, you just don't win games of Limited without executing a plan anymore. Playing random yet good cards doesn't get the job done.
You need a good curve. Not using mana on an early turn is a great way to lose in a game of Limited. Keep track of the creatures you have at each point of the curve. If you are lacking two-drops in the back half of Pack 2, you may need to take Feral Prowler over Bitterbow Sharpshooters, even though those cards have a large delta when it comes to power level.
You need enough removal. Playing Limited without at least a couple of removal spells isn't a great recipe for success. It's often why even inefficient removal spells are taken so highly.
You need a plan. Whether this plan is to be hyper-aggressive, ramp, or something else, you need to have enough cards that go along with this plan. Sometimes you should take Manalith over Rhonas's Stalwart in the ramp deck if you don't have enough fixing or ways to ramp. Even though Rhonas's Stalwart is a much better card.
The later in the draft, the more scarce some resources get (removal, two-drops). You need to be able to re-evaluate cards with respect to whatever your deck is lacking.
Deeper Pack Analysis
Most of the times, the information is in the cards you have already taken, but you can still find it elsewhere. Take a look at this Pack 1, Pick 1 from an Hour of Devastation draft.
The pick is between Bloodwater Entity and Oketra's Avenger. My current Hour ofDevastation pick order would lead me to take Oketra's Avenger out of this pack. But I don't believe that is the correct pick out of this specific pack.
When you look at this pack a little closer, you'll notice that there are a bunch of cards that are good in U/R. When you consider the fact that this pack has a fair amount of other powerful cards, it becomes quite likely that one of those cards will wheel.
Overall, just keep in mind all the information you have and look for reasons to alter an evaluation. I've given some rules on what to look for, but it is no way a comprehensive list. You can continually come up with heuristics that influence your draft, but hopefully I have laid a lot of the ground-work.
If you have an idea that isn't in the poll above, feel free to mention it in the comments!