Know When to Roll ‘em (and when not to)
Calling for dice rolls too often was a mistake that I made as a baby DM and I've seen others repeat it. It's easy to see how you get there: I've been studying up on the rules and trying to memorize which ability or skill is going to apply to what, thinking about how to set a DC and interpret an outcome so of course I'm going jump to using that. I also think that there's an element of comfort involved as well: I did not decide this thing, the dice made it so. But beginner Dungeon Masters, hell, even some experienced ones, should know: you don't need to make the players roll for everything. Sometimes things just happen.
One of my first sessions my players were putting an unconscious knight onto their cart to take him safely back to town. I think, OK they're doing a thing, time to roll dice. Clearly this is an athletics check, not crazy hard but he is in armor so... DC 12. All 5 players roll and fail. I gave the last one advantage I think because they were getting help from someone who had already tried. Well shit, now what? I had to have them sit there and wait 1d4 hours for this guy to wake up and drag his sorry butt onto the cart himself before things could proceed. Making mistakes is a great way to learn.
One way to look at it is: can they fail at this? Say the document the party is searching for is in the desk, if they take their time searching this room they will find it. If it is hidden in a drawer with a secret false bottom, alright, now we're doing an investigation check. But if it is something that is easy enough to accomplish don't make them roll for it. Yeah, I can fail to find my keys even though they're in plain sight in my own home, but I'll find them eventually and searching for them isn't exactly the makings of a riveting story. If the party finding the document is necessary to advance the plot, don't create a scenario where you can't give it to them because a couple dice rolls came up too low.
Of course the opposite is true too, if what they are doing is impossible you don't have to let them roll for it. If a 20 isn't going to get them there don't call the check.
Another way to view is: should they succeed at this? Maybe the players have come up with a brilliant plan to get the drop on the enemies, or I find this especially true for the social pillar: they've crafted a very convincing argument that is custom tailored to appeal to the particular NPC they're talking to, you hereby have my permission to let them succeed without consulting the dice. If it feels right don't let a one ruin it. Sometimes I'll do the roll behind the screen just cause, maybe if I get a one I'll make the player roll a check. At the least I'll give the player advantage if they make the effort to describe a creative or clever way to go about doing something, sort of an instant inspiration.
This is one of those things that comes easier with experience. I know a lot of people are afraid to DM because they are afraid to screw up, but that's a necessary part of learning. When in doubt drop a couple dice on the table, pretend to consult them, and course correct as best you can.
