Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
These days, with Riot creating op character after op character, it's getting harder and harder for older heroes to match up. Sivir is a key example. She only has a small niche in pushing, and that's about it. However, you never get to push nowadays 'cause of all the harass going on and the way you insta-die when Jarvan looks at you. Well, this build should change that.
Runes are not important except for the movement speed rune. Armor penetration is nice at level 1 where you can do 1/3 hp damage to a hero, but at level 3, it's meh at best. The dodge is there to make use of sivir's ****py passive.
Yes we go a strange build. However, it maximizes everything Sivir would ever need. Attack speed and damage early game, dodge for the passive, and points in the utility tree, most importantly. The utility tree gives 5% exp bonus, a 0.5 casting reduction on teleport, and 1 gold every so often. It's nice.
Why this randomness? Offense sucks on Sivir. Well it's nice, but you die before you do any damage. Defense would be good, but you still die very fast with the low hp, unless you build a warmogs (trollage). Utility tree has some good stuff in it, but you waste a lot of points. Thus, the best option is to use all 3 so they can combine into something useful.
Go regrowth pendant with a potion as starting items. By far the best starting option in the game. You can't be harassed very well, the potion is there for the wth moments (good with ignite on, you might actually live if you do it fast enough). Wait until you have 1365 gold in the laning phase, then teleport back and grab boots of swiftness and the philo stone. Many people like to diss the philo stone, but in 15 min, it pays for itself. Thus, at 20 minutes, it's pretty much free money that you're getting. After philo stone, just rush a bloodthirster. Then go zeal into phantom dancer. Infinity edge is for the massive damage output that you get, and trinity is for slowing people (get a phage first if you're getting trinity). The new item, cloak and dagger would also be good to get but i find it makes it longer to get ie.
I've tried every summoner spell with sivir with many combinations. However, i find that teleport (you gotta push, that's your niche, darn it), and flash are the best spells for sivir. Teleport is for those times when you gotta save a tower, split push, backdoor, or even a 3-man gank. Just teleport to a minion near the enemy hero while your 2 teammates have the hero cc-d and u can instantly be in the fight and damaging him/her.
Flash is better than ghost for sivir. Sivir already has a ghost in her ultimate. Besides, flash is so much better for both initiating and escaping.
Sivir's considered to be one of the best farmer's of the game. Really? I don't think so. Not anymore. A good farmer is good at all stages of the game and can kill minions fast. Sivir can only truly farm awesomely late-mid game. Of course, at that point, THEN she becomes the best farmer of the game. Anyways, if you're considering playing Sivir, don't take top or mid, unless you are the only carry or the only range. Take bottom at all times and just last hit like crazy, harassing the enemy heros when no minions are present.