For my tables, it's about generalising and ensuring the players are aware to listen to my narration when I use it.
Your journey continues as you once again launch the canoes out onto the water.
As you set out on the day's journey, who is navigating the canoe today?
[General introduction to the day, and identifies the party member I'll later ask to roll a navigation check.]
The humidity today is oppressive and uncomfortable, insects are buzzing around everywhere.
[Telling the players what the weather is like, and giving them a clue that they should use insect repellent if they have it. If they choose to ignore this, or don't have it, then Shivering Sickness becomes a real risk.]
The current of the river today is sedate, quiet enough for you all to be able to talk and plan should you wish to.
[A call to encourage players to do some in character talking or planning as they move the canoe. This is the player's opportunity to do things like search for food and water. That's the point of the planning here. If they don't pick this up, don't worry there are other ways to encourage it.]
As you've been talking/paddling/planning, there's a rustling in the tree line on the shore. Fortunately, it's just a small wild boar. It does remind you all however that someone ought to be keeping watch for signs of danger from the jungle.
[The players here might also have picked up on the idea that the wild boar could be hunted. A single arrow should be enough to kill it and boom they have food from the jungle. You're also here looking for a player to volunteer to look out for danger too. That rustling could have been a monster after all.]
On the banks of the river you see a small group of humanoid figures through the brush. One is wearing a bright red robe, on closer look you can see they have travelling with them both human guards, and skeletons.
[Call here for a history check from players, if successful they identify that this is a Red Wizard, if not just a dude wearing a red robe. They can choose to attack or not.]
The Red Wizard and their party have stopped for a rest. One of the three guards is refilling water from a small stream. If you intend to ambush them you'll need to be quiet, and you'll need to be quick.
[I turn the combat encounter into another chance to collect food and water if they haven't already].
You could also be more explicit with it.
As your characters pass through this section of the jungle there is a loud sound like the rushing and crashing of a waterfall, but there does not appear to be a waterfall in sight.
[This is basically a DM SHOUTING at players to find the waterfall and collect some more water.]
or
The rain is beginning to get particularly strong at the moment, even the most imperceptive of you realise that the weather is about to turn against you. You have mere minutes to pull the canoe to the riverbank and hunker down, or you'll be facing a strong and uncertain current.
[A prompt here not just to pause travel, but also to set up rain collectors]
It's never the same at any one description. You need to try and think of your own stuff. Players have a part to play in this. They need to be listening to narration for the clues you're dropping. If you have a party that want to go heavy on roleplay, then they have a big part to play in listening to and understanding what you are saying to them. They need to understand that when a DM says 'you feel like you're being watched' that's a sign that danger might be nearby. If you tell them that the rain is getting heavier, that's their sign to set up water catchers. If they're only interested in the hack and slash you can be a little more blunt, but you'll need a read on your players. Try and match the clues you give in your narration to the comprehension levels of your players.
For my tables, it's about generalising and ensuring the players are aware to listen to my narration when I use it.
Your journey continues as you once again launch the canoes out onto the water.
As you set out on the day's journey, who is navigating the canoe today?
[General introduction to the day, and identifies the party member I'll later ask to roll a navigation check.]
The humidity today is oppressive and uncomfortable, insects are buzzing around everywhere.
[Telling the players what the weather is like, and giving them a clue that they should use insect repellent if they have it. If they choose to ignore this, or don't have it, then Shivering Sickness becomes a real risk.]
The current of the river today is sedate, quiet enough for you all to be able to talk and plan should you wish to.
[A call to encourage players to do some in character talking or planning as they move the canoe. This is the player's opportunity to do things like search for food and water. That's the point of the planning here. If they don't pick this up, don't worry there are other ways to encourage it.]
As you've been talking/paddling/planning, there's a rustling in the tree line on the shore. Fortunately, it's just a small wild boar. It does remind you all however that someone ought to be keeping watch for signs of danger from the jungle.
[The players here might also have picked up on the idea that the wild boar could be hunted. A single arrow should be enough to kill it and boom they have food from the jungle. You're also here looking for a player to volunteer to look out for danger too. That rustling could have been a monster after all.]
On the banks of the river you see a small group of humanoid figures through the brush. One is wearing a bright red robe, on closer look you can see they have travelling with them both human guards, and skeletons.
[Call here for a history check from players, if successful they identify that this is a Red Wizard, if not just a dude wearing a red robe. They can choose to attack or not.]
The Red Wizard and their party have stopped for a rest. One of the three guards is refilling water from a small stream. If you intend to ambush them you'll need to be quiet, and you'll need to be quick.
[I turn the combat encounter into another chance to collect food and water if they haven't already].
You could also be more explicit with it.
As your characters pass through this section of the jungle there is a loud sound like the rushing and crashing of a waterfall, but there does not appear to be a waterfall in sight.
[This is basically a DM SHOUTING at players to find the waterfall and collect some more water.]
or
The rain is beginning to get particularly strong at the moment, even the most imperceptive of you realise that the weather is about to turn against you. You have mere minutes to pull the canoe to the riverbank and hunker down, or you'll be facing a strong and uncertain current.
[A prompt here not just to pause travel, but also to set up rain collectors]
It's never the same at any one description. You need to try and think of your own stuff. Players have a part to play in this. They need to be listening to narration for the clues you're dropping. If you have a party that want to go heavy on roleplay, then they have a big part to play in listening to and understanding what you are saying to them. They need to understand that when a DM says 'you feel like you're being watched' that's a sign that danger might be nearby. If you tell them that the rain is getting heavier, that's their sign to set up water catchers. If they're only interested in the hack and slash you can be a little more blunt, but you'll need a read on your players. Try and match the clues you give in your narration to the comprehension levels of your players.
DM session planning template - My version of maps for 'Lost Mine of Phandelver' - Send your party to The Circus - Other DM Resources - Maps, Tokens, Quests - 'Better' Player Character Injury Tables?
Actor, Writer, Director & Teacher by day - GM/DM in my off hours.