If below level 30, save all your IP for a bit and spam free weeks to find your favorite champs and styles. Common recommendation is 2-3 champs in off roles and 3-5 in main.
Personally I think this is an error unless you are a fairly strong player willing to commit time to throughly learning so many champs. I played a lot of champs up to gold but most were messing around in bronze 3 where I put in focus on a few champs I enjoyed enough to really learn and improve at and I climbed at a moderately fast pace.
Personally I would suggest finding 3 champs that are not often pick ban status and can cover 4 roles at least. You don't need to play all the roles, just support and 3 others. This does two things that are important, first, you can learn 3-6 champs well and that is enough to get to gold or at least high silver (I can beat any counter with heimer up to around silver 2 where I start going even, basically just by knowing his match ups and how to adjust). Second, you can focus on things you enjoy so you are willing to put more effort into learning them. It had been so many games since I played adc I had riot delete them from my account so I can't get mystery skins for them. I just tell people I can play anything except adc and we can run kill lane hot with bruisers if no one else can adc.
Personally I ran heimer top/mid Nunu jungle and Annie/Morg support for at least 90% of my serious climbing. Therefore my suggestion would be find something you love that can play two roles (like top/mid, mid/support, top/jungle, adc/mid or top, jungle/support) and learn it inside and out. This lets you spend as much IP as you want on two or three champs to get really good with, and the. fill in other needs with low IP champs.
Hope that was useful.
