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While some of it will be subjective, IME there are some things that make choices more engaging.
A choice made in complete ignorance may as well be replaced by a coin flip; avoid that. If you're presenting a genuine choice, make it so that when the PC or party approaches the metaphorical crossroads, there's already some information about how this may influence the future in major ways.
Make it so that choosing something now opens up a different set of choices later down the road. E.g. choosing to save a rival results in later getting an option to grudgingly join forces when facing a bigger fish (but only an option, as such an alliance of convenience should have downsides of its own!).
No IWIN Buttons
When setting up a major decision, avoid presenting one that has no downsides to speak of. It's fine to have situations where there's one obviously right way to act, but such situations aren't perceived as choice situations.
No GAMEOVER Choices
There some computer games which present a few options, all of which make a certain amount of sense to pick in-character, but if you choose them, they put you on a path to an inevitable gameover - in a few clicks if they're merciful. In worst cases they instead make you stuck, unable to proceed past some required point. At all costs avoid presenting such choices to players in a tabletop RPGs. If a player has a PC choose something like that spontaneously (without being prodded), very seriously consider giving a few hints about the outcome and ensure there hasn't been a miscommunication that lead to this.
A Touch of Inevitability in Hindsight
The first advice was to make choices informed. However, it's good not to go all the way with that either. Make some consequence of the choice unfold as a surprise to players and/or characters. But in a way that once the players think about it, they see how the sum of circumstances logically lead to the outcome eventually faced. The hindsight aspect of inevitability is good for plots in general, but I think it applies even more to choices. And who knows, maybe a more attentive and insightful player manages to predict this inevitability earlier than you expect; this happens at times, though since the GM usually has a bird's eye view of the hidden events of a campaign, it's easy for the GM to underestimate the difficulty of making such conclusions while wearing a player's shoes.
A Gift That Keeps On Giving
Choices can be made to be felt more rewarding in general if most choices keep producing more ripple effects down the line, again and again. Such as a recovered minor but unusual technology turning out to be moderately useful in a series of situations that occur 10, 30 or even 100 sessions after the initial choice. While at first this tends to remind of the importance of one choice, once this becomes an established pattern that is seen across multiple choices, all choices start looking more rewarding because players begin assuming that they'll also keep on giving. (Note that conversely, reoccurring negative consequences of a choice also increase the choice's perceived importance, but for some players such an experience can be unfun.)
This Content is Lost Forever
A way to emphasis the gravity of a choice is to ensure, and convey, that depending on the choice made now, something 'big' will become unavailable forever, with no chance to come back and 'pick it up' later.
No, you can't save the blueprints of the enemies' airship if you chose the easy path of sabotaging their factory by arson; no, you can't explore other solar systems anymore if you collapsed hyperspace to trap the invasion of horrors from beyond the galaxy; no, you can't tolerate living in a robotic body for long ever since your mind has been changed by the attainment of psionic powers; no, you can't ask Charon for a second chance at life ever again, because you were spotted binding the souls of the dead to skeletons for your army in a desperate defence against the Dark Lord's siege.
Again, there's some subjectivity regarding how much of that is too much and how little is too little - keep your players' personalities in mind an make adjustments. But when you want to make an unsubtle statement about the choice being very serious business, throw in 'permanently lost' content.
Consider your stance on Meta knowledge
In some games, players are never deliberately given knowledge that their characters lack. In others, it is perfectly acceptable to say 'You failed this roll, so your PC didn't notice that she got secretly poisoned during the banquet; there are no symptoms for now . . .'. Which approach to use depends on the gaming style of the group / game line / etc. Make sure everyone's on the same page about which approach is in use at the start of the game.