For the best ranks yeah, its about finding the most broken/op runes and combos. Of course you need to know how to play well too and you need to be able to see what is the powerlevel of your stuff compared to the nora. Well having a massive collection helps. Top 100 is easy to achieve with small collection and skill.
Instant trivia: one of those sentences is a joke, which one? And yea, he asked how to get good, getting limited right now is kind of pointless. You get yourself a blue name and people will say it's only because of your OP runes. But go ask what these people play... And that's why I decided to challenge myself and play the least OP runes I can, although the plan did get thwarted by my... exaggerated patience and incredible concentration power.
True winners are recognized by their "Potato!" award. Check my profile and ignore everything else because that's the only thing that matters. Earnest effort and 29.95$ monthly into my account will grant you the position you deserve in Pox community.
Learn to understand tactics. Tactics is different than strategy. Strategy without tactics is a failed experiment.
One recommendation is to create a competitive battlegroup, use many of the same champs over and over, with only slight changes to the battlegoup. This will help to learn your abilities and combinations so you can make decisions quickly when playing matches. If you spread yourself too thin, you will not be able to memorize your abilies and tend to run out of time during matches while you keep looking up your abilites during the game. Practice, practice, practice! For example, if you decide you want to play Leoss, stick with them for a while so you can memorize what your runes do. Only make small changes as needed, but keep your core runes. If you switch from Leoss to Stitched, then to UD fire amplification, to Bogghopper, to Kanen, etc., you would need to memorize quite a few runes and again, takes too much time during maches causing you to lose your turn. Look at the many battlegroup ideas in the forums. Watch the top players to learn what they play, how they play, movement strategies, combinations, etc. Then go ahead and create your battlgroups using the information you just learned.