Random Encounters and Wandering Monsters have long been a cornerstone of D&D and - just being totally honest here - they can be pretty lame. The only thing worse than a game session getting bogged down by a lengthy encounter with a random group of 1d6+1 dire wolves is when that encounter results in a PC death. That's not to say that random encounters have to suck. I think a lot of the time, GMs spend a lot of time on worldbuilding and crafting thoughtful and elaborate dungeons and so when it comes time for random encounters, it's easy to say "screw it, a bunch of goblins attack." There are ways to save time on GM prep - if you're interested, check out this post here. However, I think that well-crafted random encounters are actually vital to a strong campaign. Here are my best tips for making random encounters both fun and meaningful.
Incorporate Player Choice - The main reason that random encounters often fall flat is that they don't provide the space or flexibility for players to make any real choice beyond "Should I attack with my sword or with firebolt?" Instead, think of how to include space for players to approach and solve encounters creatively. One example I've talked about before is to let the party debate risk/reward for a potential encounter. Maybe the party comes to an abandoned silver mine. There could be some good treasure inside but those snake-like tracks leading into it look suspiciously like they belong to a naga or a hydra. Or perhaps there was a heavy downpour and a bridge washed away. Does the party attempt to cross the swollen river, risking injury or do they spend half a day taking a detour to the next closest bridge? Giving the party space to decide to engage with an encounter can create some fun RP moments and even if things go sideways, they won't be as frustrated because it was their choice in how to approach the encounter you presented. If you are going to thrust a combat encounter on the party, I think it's important to leave space for non-combat solutions. If an owlbear has been stalking the party, it may hesitate attacking as it sizes up the party. Rather than jumping straight into initiative, the party now has a chance to cast Speak with Animals, scare off the creature, or throw some food at it to cause a distraction while they make their escape. They may decide to attack it anyway but at least you've made it their choice to do so.
Tie Encounters to Worldbuilding - Another thing that so many random encounter miss is the opportunity to connect the encounter to the larger plot, worldbuilding, or theme. If the party is hunting down a goblin chieftain, an effective random encounter could be them getting ambushed by some goblin scouts. If your campaign is working toward revealing that an undead plague is beginning to unleash upon the world, they may come upon some undead unexpectedly. Or they may find the remains of travelers who came upon undead. If the theme of your campaign is chaos vs order, the party may discover the ruins of an ancient keep reclaimed by nature, or a group of soldiers under attack by harpies. Random encounter should never be truly random as each one is a way to intentionally add something new to your world to continue developing it and the larger story.
Consider the Consequences - One other way that random encounters suck is that they often feel completely meaningless. If the party is attacked by a troll, does it really matter if the party runs away or kills the troll? Does either outcome have any bearing on the world beyond that single encounter? I'm here to tell you that yes, it should. Every encounter should have consequences - good or not so good - and as GM, it's important that you consider what those are and how they play out. If the party kills the troll, perhaps the party later discovers a caravan that has been hiding out from a murderous troll and is grateful that the road is now clear. Or, if the party didn't deal with the troll, they may discover that same caravan has been slaughtered. Or perhaps the merchant leader of the caravan is angry that an able-bodied adventuring party didn't deal with the troll and now she charges the party 50% more for all her her merchandise. One of the most fulfilling aspects of playing D&D is when your character gets to make choices. Those choices feel so much more significant when the players can see clear and meaningful consequences to their actions.
What's your best way to inject some life into random encounters? Let me know in the comments below!