You can tell that the goblin is lying. versus The goblin glances from side to side, looking for any excuse to cover his lies.
You can tell that the temple has not been visited in some time. versus A thick layer of dust indicates that the ancient temple has not seen any visitors for years.
You can tell that the cultists don’t see you. versus The cultists have their back to you and their chanting has not changed in pitch, giving no indication that they’ve noticed you.
When watching or listening to other GMs, I’ve noticed something that really frustrates me. After an ability check or an inquiry to the GM about something in the game world,  have a bad tendency to say “you can tell that…” followed by the answer.
This sounds really dry and immersion-breaking. It doesn’t follow the guideline of “show, don’t tell” and it doesn’t give your players any flavor. Instead, help them understand what they see and how they can tell. This probably requires a little more visualization on your part, of course. You have to think about what that NPC might be doing or what might exist in the world to indicate the answer.
Because of that, however, you’ll end up doing more than just making the world come alive in your players’ minds. You’ll also inadvertently create more hooks for everyone to follow. Maybe that goblin is lying because there are factions back in her camp. Maybe the temple is filled with dust because of an unholy wind. Maybe the cultists are caught up in a frenzied ritual that the party has to interrupt right away.
Either way, don’t just give players answers. Give them a little picture of their world.
: I probably do it sometimes, too.