This guide is intended to get those who are hard stuck in silver, the ability to make a difference in every game, as a support laner. This specific build and champion will fall off when you start fighting plat players, so I'd recommend against using it past Gold II.

E is the best skill to max, because at level 1, landing an E, pulling the enemy with your passive, and auto attacking once, will allow you to electricute them, all in under a second. this has ALWAYS led to first blood when my team has invaded.

Later levels, the E max will reduce the cooldown on your next attempt, and apply more damage before electricute proc.

You can even hold off on putting a point into Q until level 12 if you'd prefer, however sometimes, that little extra damage might save your team. just don't poke with Q.

The best way to build for your second back, is to grab a Blasting wand and Ruby crystal, and the third back will usually decide the path you're taking. If by then you have enough for RoA, buy it outright, if not, start buying whichever Rylai items you can. Rod of Ages is a great item for swain as it gives him some tankiness, and scales very well, however most games don't go past 40 minutes, so you may need to switch to Rylai's Crystal Scepter to stay useful.

-Finish the previous RoA or Rylai's before finishing boots, as RoA is on a time crunch, from there, finish your boots for the penetration.

-As soon as you hit 9, grab Farsight Alteration, most junglers grab sweeper, and you'll be getting pinks with any spare gold you have anyways. Try putting blue wards in bushes in your jungle, for long lasting vision.

-Zhonyas is one of the most important items for swain, not to be used offensively. Don't rush into all 5 enemies and zhonyas, or you'll lose the teamfight. From the edge, try to get 2-3 enemies in your ult, if the enemy team starts focusing other people, it's safe to walk into more than those. Zhonyas at half hp while ult is active.

-Luden's Echo is great for mana, as well as a little added burst. In most cases, a simple E, passive yank, and auto will proc both ludens and electricute, putting most non-tanks below half hp. throwing a W after the yank just adds insult to injury.

-Liandries is another good Item that mostly pairs best if you had to get rylai's instead of ludens, however your W also applies the extra damage.

-and lastly finish your core support item. that extra ward won't make as much difference since you'll be running Farsight alteration.

Your job in the teamfight, is both peeling, and damage. when the fight starts, ult on 2-3 of the enemies, but dont put yourself in the middle of all 3. Focus the one that's closest to your carry. (if your adc is 1/5, and your mid laner is 5/1, it may be tough, but stick with your adc, the mid laner knows what they're doing.)

If at any point you get to half hp, zhonyas with your ult still active for the extra healing and damage output. If you're being chain cc'd, just spam zhonyas early and let them miss their important "After CC" abilities, blowing some cooldowns.

Try to keep your ult up as long as possible, but if you get down to ~25% health, pop it for the extra damage before you die, your team should be able to mop up from there.

Most adc's with quick burst work amazing with swain, while those that don't usually rely on abilities to deal most of their damage can be lacking. The only adc I would avoid supporting as swain, would be sivir, and in some cases jinx.
People with Quick burst such as caitlyn or kaisa are ideal. Ezreal is a strong lane pick, however he tends to fall off late game. But swain support works with him great as long as he attacks whoever you grab.