It's really hard to get into the game for new players.
Too much smurfs and poor explanations make it really hard.
- Always test new champs out in bot matches first
- Look up Guides, Guides and more Guides. As long as they are not from Mobafire they are gonna explain everything you need. I can recommend http://solomid.net/
- Try to test out many champs until you find a/some champs you feel comfortable with
- Once you reach lvl20+ yo should start saving up IP for a rune page. But only buy Tier3 Runes!
- I recommend playing against normal players instead of bots from lvl10-20 as you will not find many smurfs anymore and you'll want to go against players early because else you'll go into normal matches at lvl30 without any clue about the game whatsoever and just get destroyed and humiliated
- Also if you don't want to look up Guides, just use the recommended builds for your champ first. Those are mostly not the best but still good