We will need to rely heavily on our sets to show the passage of time, and there's not a lot of the usual details available to us to clue in the audience - no news reports, dates on tombstones, etc.
For Rivendell, I would like to see the seasons change over the course of the first season. So, as Season One opens, we are in Rivendell in late winter. Week to week, we can see spring come, and give way to summer. Some of the events in the 'outside world' can be referenced in the script. Going from February to June to Bilbo's return in the final episode should allow viewers to see that time is passing. Oh, and we can celebrate Estel's birthday on March 1st
I'm not too concerned with showing time passing in the frame without resorting to awkward dialogue.
I'm more concerned with the passage of time in our main story, in ancient Arda. True, we have some milestones - the formation of Almaren (Episode 2). The lighting of the Lamps (Episode 5). The destruction of the Lamps (Episode 6). The lighting of the Trees (Episode 8).
But that's just the problem - thousands of years need to pass between these events, and it's going to feel like 'yesterday' unless we show dramatic changes in the landscape. I want to show the evolution of plant and animal life to show the passage of time in Season 1, and that's....going to be rather challenging.
Flora
Episode 1: Timeless Halls, Arda is seen only as a Vision in the Void, being giving actual creation at the very end.
Episode 2: Arda should begin...lifeless. We should see barren landscapes of rock and water. We see the green of algae and mosses, but nothing more substantial than this until we reach Almaren. There, we get ferns.
Episode 3: Melkor in the Timeless Halls/Void. He ends by entering Middle Earth, in a barren rocky place.
Episode 4: Almaren, pre-Lamps - Ferns and early (ie short) conifers, cycads and ginkos.
Episode 5: Almaren, pre-Lamps - see above
Episode 6: Almaren, Lamps - TALL conifers (forests) and, during the episode, the first flowers.
Episode 7: Valinor, pre-Trees - ???
Episode 8: Valinor in the Light of the Trees - We have grass now.
Episode 9-13: ??? How to show time passing now?
And Fauna I leave up for discussion, as we will need to make a lot of decisions there.
For Rivendell, I would like to see the seasons change over the course of the first season. So, as Season One opens, we are in Rivendell in late winter. Week to week, we can see spring come, and give way to summer. Some of the events in the 'outside world' can be referenced in the script. Going from February to June to Bilbo's return in the final episode should allow viewers to see that time is passing. Oh, and we can celebrate Estel's birthday on March 1st
I'm more concerned with the passage of time in our main story, in ancient Arda. True, we have some milestones - the formation of Almaren (Episode 2). The lighting of the Lamps (Episode 5). The destruction of the Lamps (Episode 6). The lighting of the Trees (Episode 8).
But that's just the problem - thousands of years need to pass between these events, and it's going to feel like 'yesterday' unless we show dramatic changes in the landscape. I want to show the evolution of plant and animal life to show the passage of time in Season 1, and that's....going to be rather challenging.

Flora
Episode 1: Timeless Halls, Arda is seen only as a Vision in the Void, being giving actual creation at the very end.
Episode 2: Arda should begin...lifeless. We should see barren landscapes of rock and water. We see the green of algae and mosses, but nothing more substantial than this until we reach Almaren. There, we get ferns.
Episode 3: Melkor in the Timeless Halls/Void. He ends by entering Middle Earth, in a barren rocky place.
Episode 4: Almaren, pre-Lamps - Ferns and early (ie short) conifers, cycads and ginkos.
Episode 5: Almaren, pre-Lamps - see above
Episode 6: Almaren, Lamps - TALL conifers (forests) and, during the episode, the first flowers.
Episode 7: Valinor, pre-Trees - ???
Episode 8: Valinor in the Light of the Trees - We have grass now.
Episode 9-13: ??? How to show time passing now?
And Fauna I leave up for discussion, as we will need to make a lot of decisions there.