When you find the magic of reincarnation, here is what to reincarnate into.
Choosing a race for swordsage is difficult, there aren't that many that are above average.
You knew this was coming and I don't need to explain why it's good.
It's one of few races that have a wisdom bonus, I am not including the anthromorphic animals on this list (Which only work with shadow hand builds). it also has 5 DR against Acid, Cold, & Electricity, Darkvision 60 ft and Bonuses on spot, listen and a useful Daylight SLA. There isn't really any downside aside the lack of bonus feat and skill points.
Not wonderful, but at the same time, there are several subraces which are better, most notably the snow elf. One of the most redeeming features is Eternal Blade which is incredibly powerful.
Not the most fitting fluff wise but it has its own prestige class which have heard little about it. Overall the base version is best really.
Now for Swordsages there are the 2 most usal combat styles, thf and twf. Two-weapon fighting makes more sense in practise but a swordsage can't take advantage of TWF unless you mostly use boosts to make Full attacks better. If you can convince your DM to let you use Dual strike for maneuvers to attack twice. This is flawed since you can't even use Dual Strike untill level 9 for a pure swordsage.
Two-handed fighting is the more sensible option, bash their heads in and do one strike every turn. Not much can go wrong here and theres nothing wrong with it.
Archery is difficult without homebrew Diciplines, strikes don't work with bows, boosts and counters don't always achieve anything useful and stances have little impact with that hateful word, Melee
There also the option of taking a ton of abilities that give stats to damage.
You can easily get Wisdom, dexterity twice, charisma and int twice, (depending on the ruling for brains over brawn on factotum,) all on your damage, per hit.
Let me list all the different ways of getting stats on.
Wisdom from swordsage itself, it's best for shadow hand so you can dump str and get dex on it like I mentioned before,
Dex from shadow hand or a certain shortsword in magic item compendium,
Int twice, once from factotum and once from swashbuckler,
A third time is possible from flanking and some warblade class features
and dex a second time from the fighter ACF from Drow of the underdark,
Homebrew diciplines that are well made.
Falling star, well made and gives what any archer needs. Damage and the ability to do it safely.
Sleeping goddess, rather strangely named, yet nice for psionic gishes which seem to fit well with some feats in the tome.