The goal of this guide is to max out the potential of Manamune by waiting until just the right moment to get it.

I don't particularly want votes yet, but I would like suggestions. I need to test this build out more, too.

The playstyle advice is good. I'm just trying out a different take on the items.

http://www.mobafire.com/league-of-legends/build/sivir-the-bloodthirsty-mistress-secondary-build-for-1v2-61265

I've tried very had to split purchases into small bits so that you're almost always progressing (unless you totally botch a lane run). I'm also trying to keep Sivir farming for as long as possible. A lot of the itemization order is flexible, but not all aspects of it are.

Totally not negotiable: Get Tears of the Goddess as early as possible - don't delay it *at all*. Once you do so, be spamming abilities as often as you can without getting too close to OOM. Spamming them in town isn't a bad idea if you can afford to wait 10 seconds and you need 40 gold for an item or something. We want to cap this bonus before too long. The more you spam abilities, the more max mana you have, the more you can spam abilities next time around.

Also not negotiable: Don't get Manamune too soon - several items are about the same cost, and they'll make Manamune stronger when the time comes, while making you much stronger now. Sheen gives you mana. Stinger gives you CDR. These two together will help you strengthen your Manamune.

Somewhat negotiable: Frozen Mallet. I was tempted, but it was too expensive, and you're not supposed to need a ton of health to play Sivir. If you're worried about taking hits and/or enemies getting away, it might be acceptable to get Frozen Mallet, but skip Sheen and put the Zeal toward Phantom Dancer instead of Trinity Force. Later, pick up The Black Cleaver. If I test both paths and like this one better, I'll change the build. If you're hitting hard enough, then you might not need Frozen Mallet to prevent escapes, and your lifesteal should keep you healthy instead of max health.

Somewhat negotiable: Phage before Zeal. You might have somewhat better ganking potential if you do this, but it's not as good for farming. I want Phage when I gank because it's sort of like an unreliable Frost Arrow.

Negotaible: Manamune right after Stinger might be good, if you've got a lot of mana by then. Tears only grows when you use abilities, but Manamune grows when you attack as well (like 1/4 of using a skill). Stinger gives you CDR which works with the tears, but the attack speed will make Manamune grow faster, too. The attack speed/damage combination might your damage output spike if you do this.

Negotiable: If you're sharing a lane, getting Stark's Fervor sooner might be a good idea.

Negotiable: Stinger vs Ionian Boots of Lucidity. The CDRs are almost the same, and if you hug the turret a little more, then you can get by without run speed and you can lifesteal faster with Stinger's attack speed to stay in the lane. Especially viable if you take Ghost for emergencies.

Negotiable: Nashor's Tooth before Phage and Zeal. If you get Zeal before Nashor's Tooth, though, just finish Trinity Force. Getting Nashor's Tooth earlier will help your Manamune out, so getting the tooth, then the Manamune, and then Trinity Force is an option. If you get Zeal before Manamune, finish Trinity Force before Manamune.

Negotiable: The Black Cleaver instead of Phantom Dancer for those armored foes.

Negotiable: Bloodthirster instead of Stark's Fervor. If you do this, just get Vampiric Scepter instead of Emblem of Valor. Right after Manamune and before Nashor's Tooth is a good time. Stinger + Manamune will help you ricochet farm for the cash rapidly, especially if you already have Vampiric Scepter. Boomerang Blade will be stronger late in the game if you get a Bloodthirster.

These are negotiable too.

Fortify: Hopefully you won't have to cast it. Boosts your Ricochet farming. If no one else is taking it, it's always nice to have one of them on the team.

Clarity: Spam nigh-indiscriminately to max out your Tears. This might be overkill, though.

Ghost: I like this. If you're judicious with your ultimate, though, you might get by without it. Getting Zeal and/or Phantom Dancer will pick up some more slack if you miss out on Ghost, as will playing it safe.

Exhaust: Not as redundant with your ultimate.

Rally: Combos with your ultimate in team fights or when you've got a wave up on their turret.