How to play TSO

[Klown]

I have a MiFi running around with a large shield(no 'large shield sucks' comments please).

Ended up grabbing TSO who I don't play much. I've reached the Lair with *** piety.

1) Is there a way to get piety up faster? I'm used to cheitrog where I'm at max piety on D:3, these slow moving good gods are kind of odd.
2) Does Storm Dragon Armour make Plate Armour obsolete or is there behind the scenes stuff?
3) How do I play TSO in general?!

[rchandra]

1) You will get piety faster by playing faster (seeing more enemies, resting less), or by visiting Crypt and slaying the residents.
2) Storm is a bit better than plate assuming they have the same enchantment and the plate has no useful brand. Usually storm is bad because you get it late, but it has uses still, and finding it early is great.
3) Get some invocations, learn haste, haste your angels. Bless some great weapon later, preferably a bastard sword or demon weapon (or claymore, if you weren't using shields). Do extended. Die with 14 runes.

[Pisano]

I'm not sure I can write a general how to play TSO guide, but I will try to provide some insight into some of the important abilities.
Halo give a bonus to accuracy and lowers stealth. It's radius increases with piety. Note that this works for ranged attacks including Rod of Innacuracy which in the hands of a TSO worshiper is deadly, someone (rchandra perhaps) on IRC gave me this tip and it is a nice combo.
Divine Shield activate before you go into a tough fight. All of the standard comments about what shields are good/bad against apply to this ability, but you can wield a big 2h and still have a high if temporary SH value. Increases in power and duration based on shields and invocations.
Cleansing Flame can do a lot of point blank area of effect damage, especially to undead/demon enemies. vs. Cursed Toes or large groups of undead/demons it can be a life saver. It works better with higher invocations from what I understand. This does not harm your Divine Warrior buddies which is important.
Summon Divine Warrior is quite powerful as deva and angel allies can dish out a ton of damage (especially to undead/demon enemies) and last a long time at high piety due to bless allies. Every kill they get they have a chance to be healed, or get extended summon duration. Be careful not to attack these guys (or any allies) as you will get penance. This has a pretty heavy piety cost so you won't be able to spam it.
Bless Weapon - you can use this once and Holy weapons are generally only useful in Crypt/Tomb/extended so save it until you have a good weapon and a need. I've won 3 games with TSO and never used this but they were all 3 rune games.
Various passives: Protection from negative energy - a passive rN+, rN++, or rN+++ - nothing much to note except that rN+++ makes crypt/tomb a lot easier. TSO will also protect you from harm where he will save you from a killing blow (sometimes) at a cost in piety -- this is obviously awesome though I don't know likely it is to happen.

I generally raise invocations to the point where Summon Divine Warrior has a small failure chance as it is a nice get out of jail free card. Late game I might raise invocations more depending on the kind of character and whether I'm relying on cleansing flame for damage or not.

[Tiktacy]

Just a few general tips:

-TSO's blessing is better on weapons with higher base damage
-Hasted angels are incredibly powerful.
-TSO's negative energy resistance does NOT make tomb easier in the same way Kiku does.
-Piety will become much easier to raise the farther in the dungeon you go.
-Shields aren't worth investing in just for his shield invocation.
-Do not get a false sense of security while following him. Having angels and AOE attacks on your side can sometimes get to your head and make you think you are invincible. You aren't, so don't let it get to you.
-Using an angel in a corridor while in range of an enemy that can kill you can make a good meat shield for escaping. This should probably be a last resort though.

[Osgoodbad]

I've never started the game worshiping TSO, but I have switched to him several times for the endgame. I agree with most of what was said, but something that nobody has mentioned so far is that you regain HP for killing evil/undead/demons. In a lot of ways, he's kinda similar to Makhleb, in that he heals you on kills, supplies allies (that unlike Makhleb are always friendly) and provides you with an invocations-based AOE attack, rather than beam attacks that cost HP. I often bless an axe, because I've found it useful to be able to simultaneously heal (through the death of lesser demons) while I focus on the main threat. But axes are pretty unpopular around here, so take that with a grain of salt. The divine halo also prevents anything from being invisible (including yourself) so a source of see invis is no longer necessary.

[tompliss]

Cleansing Flame [...] This does not harm your Divine Warrior buddies which is important.

IIRC, it still hurt the enemies that are attacked by your angels, incurring penance.