Without knowing the details of your armies, here's a few basic tips vs Necrons:
Focus fire - this one is so important that its probably already obvious to you - kill your targets dead so they don't start coming back. It important to start thinking about this before you start moving your models, to give yourself as many options as possible to focus your shooting and assault onto the highest priority targets
- Put a big nasty shooty unit next to your Farseer (you have a Farseer right??). When they use VoD or
DS destroyers, trigger the Forewarned stratagem to get a free round of shooting. The bigger the unit the better obviously (I use a Scorpion
SH Tank
). Its one of the best Eldar stratagems.
- Psychic: Necrons struggle to fight it, so make use of this. Things like stacking heaps of buffs onto a Shining Spear unit for example, to make them super tough and extra fighty.
- Unless there's a great reason not to, save the use of your 'Lightning Reflexes' Stratagem until your opponent fires off their big tesla unit (this eliminates the extra effect on 6's).
- To fuel your stratagems, you need at least a battalion. Use the min troop squads (ideally rangers) to screen the enemy deep strikers and keep them at arms length from your core firepower units.
Also, consider Illic Nightspear if you play Alaitoc and worry about facing destroyers. He will almost certainly kill one per turn thanks to his bonus vs Necrons and will pay for himself very fast.
