Not too high level, and not too many monsters - you must be strategic with a small budget. To get to silver3 you need 15,000 collection power, and there is your first challenge - which are the most important cards to compete in silver?
In this post I document how you can be win in Silver with a lvl1 Summoner - you will need to select a strategy, in my case Alric + Lobstradamus + Venari Wavesmith.
Take it slow, your 1000 DEC is precious!
RE: Sneaky sneaky quest strategies - Which Splinters do you Sneak with?