I dont play dark elves but my dad does and i have helped him build good lists and know some good stuff(hope you dont mind that i dont actually play them)
I would go with an army based around magic, remember dark elves can use as many dice as they want, i would field something like this for lords and heroes
Supreme Sorceress
Level 4
Dakr Pegasus
Focus Familiar
Talisman of preservation
General
With this you have a powerful sorceress woh can fly up on her pegasus, hide behind a building or some terrain like that, then send your focus familiar(lets you put something within 6 inches that you can cast spells from) outside the building because it cant be hurt, then next turn if they are coming to get your sorceress fly back, she also has a 4+ ward save to protect her adn to keep her from dying from anything that actually can shoot or attack you
Death Hag
Cauldron of Blood
This is amazing, cauldron stays until everyone with it dies(4 wounds for the hags and the death hag) and everyone with it gets a 4+ ward save and it gives either killing blow, 5+ward, or +1 attack to one unit within 24 inches, this is very good if you can always play this
Sorceress
Level 2
Sacrifial dagger
Sorceress
Level 2
Talisman of endurance
Channeling Staff
These two will boost your magic a ton, stick the level 2 with sacrifiacial dager in a big unit of crossbows, and the other one in another unit of crossbows.
Everything else looks okay, you might want to put the cold one knights in one unit of 10, and the crossbows into two units of 19
Other than maybe doing those this looks like a pretty good list