Hello there fellow Splinterfans!
It is unfortunate that Splinterlands is now down due to server migration issues and we can't play Ranked matches for the next 1-12 hours according to the Discord channel. It is during times like this that we can allow ourselves some rest and reset- take the opportunity to maintain your decks!
This is how I tend to work when there is downtime:
- Identify which cards I have not been using (I tend to have duplicates of the same card from rewards).
I have no idea why I bought this card but I have never used it once. AT ALL. So if you'd like to try out an Exploding Dwarf, please rent it from me 
List the selected cards up for rental! It's the easiest way to earn a bit of income to defray the cost of the cards. In the long run you'd have broken even.
Find weak points in your Splinter specific deck. You can know this by watching your battles and identifying cards or abilities(Or lack thereof) that are a liability to you.
Buy or rent cards that solve or minimise that issue! I bought a Lunakari Mistress and 2x Evangelists (Yes I like it THAT much) because my Life deck sorely needs to bolster its range attacks.
Hope this helps and I wish to see you in the Ranked battles soon.
Take care!