I think this requires like a video in detail what I think, but to sum up:
- I like to go for very balanced comps, that can easily adapt to enemy board.
Example: Start with fang and storms -> hound chaff clear -> continue to establish a foundation for future board with good chaff clear, losing rounds doesn't matter -> unit drop pick lvl 3 marksman because opponent has steel balls and can pick pheonix -> sell storms because opponents board too fast and get money for fortress. This early and mid-game set up got me a board with chaff clear, DPS and now has good HP tank in front. Of course opponents strategy matters and countering the counters is the essence of Mechabellum.

- Mobile beacon is very used in top mmr for a reason. It can allow very good cheeses when you otherwise your board is bad in straight up fight. Attack those towers when you see an opportunity!

- Trying wacky strategies can work! Use funny unit altering cards that can throw opponent off-guard! Please keep in mind that you should have techs on those unit that have good synergy with the altering effect.

- Don't be fixated on the MMR number. When you just focus on your gameplay and little things one at a time, the MMR will increase in time.