In Epic, a few things are mandatory:
1) Divine Power. You need a way to get it, or else your BAB will be stuck in the crappy Epic BAB progression. You will probably have to take Arcane Disciple for this, and find a way to persist it. the other option is really taking Rainbow Servant and then taking Extra Spell a couple of times, because you won't actually get new spells known at all.
2) Wraithstrike. Epic monsters get a lot of AC easily. You want to be able to hit them. I don't have good suggestions for how to get this.
3) Shapechange. Basically either you have it or you suck. This is a harder one, but not impossible. What I suggest is: Take a level of Bard at 21, and get the requisite feats to get into Sublime chord. Then up your Cha a little, so that you'll be able to cast 9th level spells.
4) Cheap metamagic. That won't be your forte. Get one of your mates into Incantatrix so that he can persist your spells.
5) Immunities: Basically Epic moves off the RNG completely. Which means that saves WON'T save you. You need to be immune to death effects, to ability damage, ability drain and some other things. There are some items that help, here. Also, the spell "Veil of Undeath", if you can get that cast on you somehow.
Unfortunately the Duskblade is a poor class in Epic - while it stays fairly ok offensively, it's simply not versatile enough to compete with full casters. However, if you're playing with a lot of mundanes, then you still have it easy, since they will suck more.