I still consider myself a noob, feels like just yesterday I made fun of my girlfriend for playing this game and well... Here I am now, addicted to it!
Gawd! I remember I hated this game as every other game I played involved some sort of shooting, either CoD, BF, or World of Tanks and could not stand how she talked about champions this and champions that. The term mana didn't even exist in my dictionary neither did magic or energy in any game I've ever played.
Things I've learned so far...
Support:
-Never CS steal your ADC or APC early game.
-Do not tower dive unless you know for certain you have the kill.
-Your job is to either heal your ADC/APC, grab/stun/snare enemy ADC, or poke/harass enemy ADC/APC and slow down their CS
Starting items: Health Pots, Mana Pot(s), Stealth Ward, and Support Item(Ones that generate gold for you).
Once you have enough gold, buy more wards and ward every bush (usually bottom 2 and the mid bush). If enemy JG comes down chances are you will see him/her before they dive on you.
Top Lane:
-Do not tower dive. Only do so if you have the kill.
-Focus on farming CS.
-Whenever possible, harass your opponent. This slows down their CS farming and allows you to reach level 6 first.
-When your JG pings or is on his way to gank your lane, lure the enemy top laner closer to your turret. Take unnecessary damage if possible to lure him. Once he's in your JG should be right behind him.
Last hitting is something I am continuously learning as it varies as you level up. At the beginning you want to let your minions do the damage and once you see a minion with a smudge of health left, auto attack it or use your abilities if you can. The more damage you dish our the easier last hitting becomes. Again it varies depending on the type of damage you do. Basic attacks depend on base AD (I believe). Eventually around mid game you will be able to last hit minions when they are approximately 50% (Maybe 30%) or lower in HP.
Jungle:
Since last season, jungle has changed a lot. I mean a lot. Now your upgrades to Machete matter. It used to be an item that only mattered at the beginning and would be sold off mid to late game. If your jungler is good at chasing, like Vi, Aatrox, Rek'Sai, Skarner, Hecarim, Diana (these are some of the JG I use that have gap closers or speed boost), you might want to go with the blue upgrades that allows you to smite enemies and slow them. For other champions like Elise, Darius, Nautilus, Shyvan who have AOE attacks you might want to go with the purple upgrades that give an AOE smite and makes clearing jungle camps much faster.
Ideally you want to keep track of your Dragon (Its yours, do not let enemy JGr have it) and keep it ward it. I usually clear my JG and try to gank bot or top lane. If I get a kill or assist I can get to level 5 fast. Once that is done, I ward my dragon, and by this time your first buff should be up. Sometimes I grab my buff first and then proceed to ping dragon and take it or other times I just ping and take dragon and get buffs later. Bot and Top lane IMO are the most needy lanes in which they usually need ganks whenever possible as they are isolated. Mid lane has bot laners or top laners that can come down and help it in case it gets into trouble.
Runes:
Runes are perhaps as important if not more important than masteries. Everyone has their own pick of Runes. Me and my gf argue all the time of flats vs scaling. She argues that scaling is much better for bot lane ADC/APC as they scale faster and better late game. I argue that having early game advantage gets you to scale better mid to late game.
My recommended runes:
Flat AD Marks
Flat Armor Marks
Flat Armor Pen Marks
Flat Magic Pen Marks
AS Marks
Flat Health Seals
Flat Armor Seals
Flat AP Glyphs
Flat MR Glyphs
Scaling MR Glyphs
MS Quints
Health Quints
Armor Quints
LS Quints
Flat AP Quints
Flat AD Quints
With runes, I recommend only Tier 3. I think tier 1 and 2 which I bough when I first started, are a waste. Also, a healthy number of rune pages like 3-4 is strongly recommended. You need one for AD, one for AP, and one for either Support or Tank.
Glossary of Terms
AD: Attack Damage / Physical Damage
AP: Ability Power
AS: Attack Speed
MS: Movement Speed
LS: Life Steal
APC: Ability Power Carry (Mage Assassin)
ADC: Attack Damage Carry (Marksman)