Sivir is a very much looked over attack damage carry. While most people see her as a joke champion I see her as one of the best attack damage carries in the game. Her mechanics are fairly simple, giving her a relatively low skill cap, so almost anyone can play her.

Really just use your attack damage runes.

Use standard AD crit masteries.

Sivir's main source of damage comes from her boomerang blade. TO do well with Sivir you must master hitting it on the way out as well as the way back.

Her W is mainly used on minions to hit champions out of her basic attack range. Once you hit level 6 it also gives you a nice attack speed buff to help in fights or taking towers. Make sure not to use it on towers if an enemy champion is under it you the tower will agro you.

Sivir's spell shield is one of, if not the most under rated ability in the game. You can bait out spells in lane for mana, block global ults, and never get hit by a thresh hook. Most people will use it wrong, you have to wait until the ability is in the air before using the shield, as it only lasts 1.5 seconds. While most people mas the W second I max this second because the level 5 ability is on half the cooldown, which will constantly save you.

Sivir's ult is nothing special, it is basically a buffed talisman. Use it when running away or chasing down enemies. The only good thing about it is the attack speed buff it gives to your W, allowing you, with your stattik shiv and W to do a surprising amount of burst damage.