Vyvyan Basterd
Adventurer
Step 1: Do not prepare battle encounters. Prepare stats, agendas, and motivations.
I’m sorry, but I just don’t believe that you don’t ever make encounters that you know will be battles.
ExploderWizard's advice and making encounters that you expect to turn into battles are not mutually exclusive.
Yes, sometimes a creature's agenda could be as simple as "kill all living things that come into view." But that isn't typically going to be the agenda of living creatures. Even animals have an agenda of "get food without getting killed." And the craziest of goblins will still want to protect their tribe, not usually fighting to the death of every last member.
An encounter can start as a fight and take a turn away from combat midstream if the agendas and motivations or the creatures and the characters coincide.