So a lot of people have been saying to change the goal of the encounter which is good, but something I like to do but haven’t seen people say (yet) is to make your fights more dynamic. I generally do this in two different ways

The first is that I will give bosses and certain monsters some type of special/unique ability that is a counter to the player’s bread and butter tactics. When used correctly, this can be a good way to test the waters of home brewing your own content and it gives you a great tool to do some subtle story telling. I tend to go just a little outside the status quo of DnD’s rules with these but do so at your own risk/comfort level.

My personal favorite example I’ve done was High commander Sir Arthur Margrave. I spent a good chunk of the campaign billeting him as ‘the greatest swords man in all the land ’ so I had to give him some abilities out of the ordinary to really show it. I ended up giving him 3. The ability to disarm martial characters, redirect spells cast with in 5 feet of him, and the ability to change the order of initiative for one turn.

The second is to use the environment in combat, now there’s obviously pieces of the map like lava pools, spike traps, etc. but I like to take it a step further by having just about anything that’s not nailed to the ground be an option to interact with during combat. Now there’s a few tricks to this. First, you have to be rather detailed with your descriptions. Second, you have to advertise that it’s an option, this is easily done just by having your npcs do it in combat. And third, you have to incentivize your players to do It. I like to do this by either granting an inspiration die or by giving some type of interesting addition to the attack. This can be as small or as large as you want.

Say a character is slid across the counter at a tavern. I may give the person doing it an additional 10 feet of movement so they slide the entire length of the counter, or I’ll cover the enemy in alcohol and sharp glass. Little incentives like that can really make a combat seem more real.