Well, we're a few days into the season and I'm almost at Silver 1. Its actually been an interesting experience given how vastly different it is from bronze, and I figured I'd mention what I learnt so far and hope it'll help out people who are considering transitioning to Silver.
1. Card variety is important when every battle has a ruleset
This to me is the biggest difference between bronze and silver. In bronze, you occasionally get standard rulesets as you get matched with players who don't have the power and/or rating requirements to qualify getting rulesets yet. (or all the time if you're in bronze 3)
That's not a thing in silver. Every single match has 1 or 2 rulesets, and it also means certain splinters will be banned from battle and starter cards will get trashed. Picking one or two splinters as your main focus for battle is fine, I myself stick to life as my main splinter. But having a backup plan of lvl 1 cards in other splinters will give you a chance to fight back.
2. Higher DEC rewards makes renting really cost efficient
Silver 3 and up you usually earn 10+ DEC per win even without a win streak. This is obviously really huge and can basically pay off a few day's worth of rentals in a single day of playing, even including what you rent for power.
Obviously this depends on how strong of a card you rent and its cost. Llama & Kron is a ridiculously high bar to make back from even with the increased rewards in Silver. For me, I mainly use a lvl 2 Lorna with lvl 1 - 3 cards, so renting these cards plus any other I may need for battle cost me about 30-40 DEC for 3 days, and power is another 60-70 DEC or so. I can make the total cost back from a day's worth of battling while trying to do my daily quest and what I get from the other days is just pure profit.
3. Use Peakmonsters for renting power
I cannot stress this enough. USE PEAKMONSTERS. The in-game market doesn't tell you the collection power per DEC, Peakmonsters does. So if you want to rent a hell of alot of power on the cheap, just go to Peakmonsters and look around. Using the above picture as an example, 13.5k power is 24 DEC, which is about 2-3 games to make back at low Silver 3, and you can find others that are even more cost-efficientif you look around.
4. Try to switch things up abit when the rulesets let you
What I mean by this is for example in melee mayhem where melee can attack from any position. You don't have to fill your entire board with melee just because the game says you can. Nothing is stopping you from running a full board of ranged or magic to confuse the hell out of your opponents. Similarly, always remember that water is not the only thing with magic. You can just as easily run an entire magic comp in life and death as well or go full ranged with selenia sky in water and chances are your opponent isn't prepped to handle it unless you've been doing it alot.
Link to battle: https://splinterlands.com?p=battle&id=sl_a38841107bff6acf76c0b6aed60b159d&ref=eldrenora
5. Water's lvl 1 stuff is still good to use
While they're no longer broken like they were in bronze, both Alric and Bortus are still usable summoners in silver at lvl 1, and the venari wavesmith is still REALLY GOOD. Which is actually kinda important, because their rentals are expensive so don't think you need to need to max them out to what Silver allows, (you can if you want to) as they are both still usable.
Here's a link to that battle: https://splinterlands.com/?p=battle&id=sl_37f5d7fcca3e73eb3ec60a199ad1f177&ref=eldrenora
Final Thoughts
So yeah. That's what I learnt so far in Silver. It isnt particularly scary once you get a rough idea on what to do, but climbing is definitely harder than in bronze. Do leave an upvote if you enjoyed what I wrote and let me know your thoughts!