Taken with permission of Skavenblight
This will have to be very generalized, as I do not have the new
High Elf book yet. Against Horde armies, the best tactic I have
found is to deploy in the Echeloned line formation, with your
hardest hitting troops (Dragon Princes, Silver Helms, etc.) on
one flank. Use a good, large Spear unit to anchor the other end
of the line, deployed at the very edge of your deployment area
closest to the table edge, use this unit of Spearmen to pivot on,
the rest of your line should alternate Archers and strong
Infantry. Hit the enemy flank with your flank, break it, pivot
your whole line and roll up the enemy's line. Use Shadow Warriors
as skirmishing screens to slow down the enemy on the opposite
flankfrom your hard-hitting troops, use repeating bolt throwers
to support your army and to weaken your opponent's largest units,
concentrate artillery and archery on the unit/units that you will
be contacting first in close combat, then move down your
opponent's line, concentrating fire on units as you go. Don't
scatter your firepower all over the place, it is much better to
concentrate on his best units or the units that you will be
attacking first. Remember, your opponent will have you
outnumbered, so keep your line together and protect your pivot
unit, don't let your opponent break your line. I lik to use at
least one unit of Ellyrian Reavers armed with both bows and
spears as a reserve, because they are both fast and flexible, you
can rush them to any point that needs aid. There are other,
stronger troops than the Reavers, but none that are as versatile
for use as a reserve. I also like to use Reavers to support my
heavier Knights on the flank, set them up to the flank, and just
behind your more heavily armoured Knights, move them over to fill
the area that you are not allowed to set up in using their march
move, then you can't be flanked, always keep the Reavers slightly
behind and to the flank of your other Knights, as they are there
to protect the flank. Use their missile fire to weaken the unit
your heavier Knights will be charging. Always use standards and
musicians, in any unit that can have them use magic standards.
The Great Eagle is the best deal of any monster available to any
army, they're great for attacking your opponent's artillery, and
his rear areas, and harrassing his magic users to keep them from
casting spells at your troops, magic users can do a lot more
damage than the cost of a Great Eagle, so if the Great Eagle can
keep the magic user from attacking your best troops, he has paid
for himself already. Unicorns make great mounts for female Elven
mages. This is about the best I can do until I read the new book,
but one thing I do know from reading White Dwarf #209, High Elf
Archery may have just passed Wood Elf Archery, that means they
are very, very deadly, and you should be able to handle the large
units of cheap troops your opponent will be throwing at you much
better than in the past.