How do you designate what units have activated during the unit phase?  You should be able to look at the board quickly and see what units have gone.  What about tipping a guy on its side from the unit or putting some kind of marker down next to it, maybe a white chip or somthing?

Thanks

Yeah, markers of some kind come in real handy, particularly when you have a lot of units on the table.

In my group we just remember what each other has activated. 

If a marker of some kind is what you prefer, I would suggest the floral section of your local hobby/craft store and pick up a bag of small glass blobs. They should work out as a cheap, easy "unit activated" marker. 

I use the power of short term memory :D

Unless you are playing huge games or moving at the speed of evolution, memory should be fine.  At 300 points, most lists I've seen have between 6 and 12 units.  I play with cards and will use them to keep track by flipping them over, especially if I'm running a list with 10+ units.

You could also turn the unit leader to face your side of the table after the activation, and turn all of the, back at the end phase.

I use the unit cards and turn them 90 degrees when a unit activates. I started doing that in Dust Tactics because I kept forgetting which units had activated.

Well you could use the unit cards that come with the units in the boxs that are meant for Tactics and just flip them over when you activate the unit. Or Print of the custom warfare unit cards that you can find on Boardgamegeek and flip those over to indicate an activated unit.

After a unit has acticated I put an upside down Reaction marker 'blank' to show it has activated, and those with reaction markers get them flipped over to their blank side to show activated even if they have supression markers.

It works for me.