The key for Silver 1 is to max summoners first to the right Silver level. And then the cards for it. But is debatable. Once upon a time I reach champion with 6 max level normal summoners Chaos and one level 1 Yodin Zaku

Level up some summoners to max and the the Common cards of that splinter like Fire. Rare summoner and Common cards max. Will get good results. Then go to water and so. By the time you get 3-4 summoners you are quite competitive. Neutral work for all splinter. Upgrade those too.