Congrats on making silver.
Way to go forward: Pick 2 or 3 splinters and get max level summoner for silver plus good monsters.
Viable strategies are e.g. earth with heals (golem, earth elemental, princess). Water splinter with magic spam or low level yodin with snipes.
Always try to be max level that your league allows.
Just rent a splinter with monsters for a day and see if it fits your style.
RE: CONGRATULATION LEAGUE UNLOCKED!!!!