Swain advice?

I get tear on my first back and always level E first, it's your biggest cash cow for big damage as it increases the damage of all your other abilities. W's CD and cost are too punishing early.

Swain is a terrible pick into Heimer due to his low mobility. I use Xerath as my counter pick on Heimer lanes.

Forget Athene's entirely, it is a total waste on Swain because of his passive. RoA will provide you with all the mana you need.

You'll usually want to get WotA and Spirit Visage on him as well, but Spirit visage is optional (usually only for if you are getting bursted to quickly to sustain through it).

Tear may be a strong pickup on Swain because of the buff to RoA and Seraph's build path, but if you are getting it for the mana, it is a wasted slot.

Swain is usually able to out sustain most lanes if you start either Flask or D-ring (most people start D-ring) your harass combo should usually be E>Q>W, E first for the bonus damage, Q second for the slow to line up W more easily, and W to hold them within range of your Q longer. If you pull off the whole thing, you can usually chunk someone out for over a third of their health at once. when team fighting, you want to get to the back line as quickly as possible and then dump your damage on their carries. Swain is also one of the few champs where it is actually ideal to Zhonya's after taking a lot of damage rather than before to avoid it, because your ult keeps healing you through the stasis often allowing you to regain about 300-400 health with ease between the base heal and your WotA.

First, you need to have a really, really good control of Swain because

1. Unlike many mages, two of his main skills are single target Dot spells. You have to actually approach to enemies to attack and take some risk.
2. His ult uses lots of mana
3. His Nevermove(W) takes 1.5 sec to root enemies so you need a good aim.
4. You have no escape route except W, which is quite easy to avoid. That means you are very susceptible to ganks.

Search Swain Bird is the word guide in mobafire. That's probably the best guide.

Don't buy any mana regen item. Swain's ult mana expenditure increases 5 per sec, with base 25 sec. You can't use your ult for a very long time and athene, morellonomicon, and even blue buff can't catch up with that.

Build RoA first. It gives you mana, health and extra AP in each 1 minute, increasing Swain's tankiness. If you are doing REALLY bad, buy three Doran's ring as a "fake RoA". This is why many conventional AP champs can easily push him in lances but can't kill him fast without good gankings. They eventually run out of mana and keep AAing or go back.

I usually pick Tear and other normal AP item like Blasting wand, then sell Tear when I need other items and earned about 350 mana. Not many people know this, but the extra man will come back once you re-buy Tear.

Since RoA is enough for most of games, Seraphs embrace may not be the best one, but still a decent choice when you are fighting agaisnt super tanky champs By the late game, I usually have rabadon, Void staff, Spirit Visage(for more heal), Sorcere's shoes, RoA, and Abysal Scepter.