The biggest thing IMO is to
actually call for a roll. Without a roll, no tension... And a lot of people seem to want to play 5E without asking for skill checks.

It might not be "interesting", but it makes it actually a challenge.
When it comes to exploration and social challenges, removing the roll basically just makes it story-telling. Yet more people want ways to make these things challenging...
shrug
While I don't necessarily think that a
roll is required, calling for an ACTION is certainly required. It's actions that have consequences--rolls simply inject extra uncertainty. Players often avoid making hard decisions, because hard decisions mean taking some action, and thus consequences. Rolling is just one subset of actions.
The main problems I had with skill challenges, at least the way they were run was that you had to have X successes before Y failures. So it didn't matter if the first thing you did should have solved the problem, you still had to pass the rest. It became a game of "who's got the highest ability for the next skill" because it didn't really matter what you did, it ultimately came down to did the player roll good enough to beat the DC. Did that happen X times before you failed Y times? Creative solutions, by and large, were not allowed.
Maybe you had a way of doing it better, and in my home game I pretty much ignored them after a while, but that's the way they were used in practice.
Anything that can be solved that easily
should not be a skill challenge. Literally exactly the same as "anything that can be resolved in a single act shouldn't be a combat," or "anything that can be resolved in a single act shouldn't be an adventure."
Now, no DM is perfect (I certainly am not!), so it's quite possible for any of the above things to happen in actual play. You didn't see the one-action resolution for something ahead of time. There are AFAIK only two valid responses to that:
1. Level with your players. "Hey guys. I goofed, I didn't think of that as a solution. I'd really like to proceed with things as I had originally planned. You totally outwitted me, so props for that, but can we skip this obvious solution and go through this as I'd planned?"
2. Accept it. "Wow, alright, you guys totally solved that immediately, here's your XP."
No rules--whether for SCs, combats, adventures, campaigns, whatever--have ever said you should enforce continuing on if it doesn't make sense. That people cut slack for all sorts of older-school rules that run into problems like this, but don't for something like Skill Challenges, continually upsets me.
The solution here is to make skill challenges a dynamically evolving series of obstacles. It shouldn’t be one thing you need X successes before Y failures to complete, it should be a whole encounter, which changes in response to your actions, and is fully resolved after X successes or Y failures. When the player suggests a creative solution to an obstacle, you narrate their success (or failure) and then present a new obstacle. Like Moves in a PbtA game.
Absolutely, 110%. Each action should change the state of play, just like in combat.
But, yeah, most modules weren’t written that way, and most DMs didn’t run them that way.
Sadly...this is also 110% true. The modules were terrible, and while the actual rules were reasonable and not as badly-written as I had originally thought, the vast majority of DMs ran them in the worst possible ways. Dry, static, bullheaded, utterly mechanistic, and purely down to "which threshhold do you pass first." Nothing like what they should be.
As I've said in other threads: if many people used Reaction rolls (just as an example) incorrectly, that doesn't mean Reaction rolls are a bad mechanic. But, just like many other parts of 4e, people often had an initial antagonistic reaction, and interpreted absolutely everything as though it had to be perfectly micron-precision mechanistic at absolutely every level of play....sucking the fun out of the game purely in how they chose to play it,
making it "MMO-like."