There are a few other things to also keep in mind when designing encounters, and this comes directly from the GM section of the Master edition;
Timers: Something is always happening when the timer hits 0 then reroll the timer die
Threat: There is always some kind of danger lurking around every corner, traps, monsters, diplomatic incidents, etc.
Treat: This is some kind of clue or big puzzle piece to the encounter, a weakness in the enemy that can be exploited, or an environmental hazard that can be used to the player’s advantage.
You can fine-tune your encounter with the following;
Damage: If the foe(s) you have placed in an encounter space seems to be ineffective, increase their damage. If in the middle of a combat offer an explanation as to why the damage has increased. This is the simplest way to increase the pressure on PCs.
Disruption: If your encounters are flat 2 dimensional spaces filled with just monsters it becomes a hack-and-slash race. By introducing disruptive dangers the players will have to find ways to navigate the encounter space and combat their foes or achieve their goals. This can be simple winds making ranged combat Hard or complex disruptive dangers like a wildfire that fills the area with thick choking smoke (Con defense per round to remain unaffected) and the fires fell trees every 2d4 rounds potentially cutting off escape routes, finally the heat of the flames do 1 point of damage per round, Con Defense to negate per round.
Lastly is Durations: In my previous example, I used a wildfire, set a reasonable duration for doom or bad stuff to happen, then when conditions are met based on the timer things start happening such as the “wildfire spreads cutting off escape to the city”.
These are ways to challenge a party that is not directly combat but can be part of combat.
Imagine a party having to fight a dragon in an open field of tall grass that is on fire. The Target Number is only 13 but they need to make decisions that matter.
•“Do I stay in place and take shots at the flying dragon raining fiery death upon me or flee to the cover of nearby trees?”
○The player may think “I can hit the dragon but I don’t know if my attack will do anything and even if it does I am sitting out in the open surrounded by rapidly spreading fire.”