So here is my guide to one of my favorite champions, Swain. Rather then going in-depth about what strategies you should be using I'll be sharing my build with you and support it here. I may still add strategies later on if this is well received.

Pros:

* Strong DoT spells
* Good CC spells
* Hard to kill because of high spell vamp stats

Cons:

* No means of escape
* Mana hungry

When playing Swain I usually choose Ghost and Ignite for my summoner spells. Ignite is an essential spell for Swain because it will boost his DoT damage even further. I find enemies underestimating his DoT damage a lot even without Ignite, so this will give them even more of a surprise. Whether you take Ghost or Flash is a matter of preference. Most people prefer to use Flash on Swain to take more out of your Decrepify spell or get into the center of the enemy team with Ravenous Flock. I personally find Ghost to be a better escape mechanism though, and since Swain has none of his own I find this the better spell to use. I don't think any other summoner spell is a good spell for him though.

After completing my Sorcerer's Shoes I usually rush Rod of Ages and Rylai's Crystal Scepter because these give you a very considerable amount of ability power, health and mana, which is basically all you want and need. The slow from Rylai's Crystal Scepter is also very nice considering that your Ravenous Flock hits all surrounding enemy champions, and thus also effects the entire enemy team in team fights. Will of the Ancients will boost your spell vamp and also give your allies a nice aura. After this I usually build Spirit Visage, and from this point you'll be practically unkillable. All that's left to do now is to get more ability power, and what could possibly be better then to build then a Rabadon's Deathcap to achieve just that?

There are several items that are good to use for Swain aswell, but are very situation dependant. After all, there is no point to keep stacking ability power if you keep dying. This is when you'll want to build some defensive items.

There are several factors to consider here. Is your enemy team AD heavy? Get Zhonya's Hourglass. Is your enemy team AP heavy? Get Abyssal Scepter. Is your enemy team CC heavy? Get Banshee's Veil. Still doesn't work? Get a Quicksilver Sash. Or perhaps your enemy team considers you too dangerous and they start stacking magic resist? Answer them by building a Void Staff.

What I also see a lot of people build is an Archangel's Staff, which I think is a mistake. Taking a look at the stats it does look like a nice item for Swain, mostly because it gives you a massive amount of mana which is really nice considering Swain is a very mana hungry champion and gives you a ton of ability power and increased mana regeration to boost. I still think this is unnecessary though, especially because the mana is the sole reason to get this for most people. My mana problems are usually solved after getting the golem buff, which already allows you to keep your Ravenous Flock on during the entire team fight. Keeping this in mind, Rod of Ages and Rylei's Crystal Scepter's stats are far more useful to Swain.

So this is how I usually build Swain. I hope you like it. Feedback is very much appreciated so I can keep improving it. Strategies may be added later.