I've suffered with them for about 20 years with varying degrees of severity. I don't have a known trigger though sadly, other than excessive tiredness.
My usual warning sign is a 'tingly' numbness in one of my feet. If I pop my meds (Sumatriptan) then, *usually* it won't hit full fruition. If I don't, then the numb patch travels up one side of my body over 15-45 minutes, progressively numbing me, until it hits my face/head. At this point, I tend to look like I've had a stroke, I lose the ability to speak and see, and then...well then comes the pain. Completely debilitating between the aura and the pain. I'm prescribed Tramadol for the pain, but not even that touches it. Usually, I'll dose up on triptans and pain relief and try and sleep it off. The after effects can usually be seen for 1-2 weeks afterwards (poor co-ordination, brain 'fuzziness' and a feeling of drunkeness).
Then sometimes I'll have very little warning until I start losing vision. I'll get a bright spot (like you've looked into a really bright light), which grows until I can't see at all. That will pass, and then I'll be wiped out with a crippling headache and nausea.
And THEN there's the ones that wake me up in the middle of the night. Generally these follow the same formula as the first ones, but I can't catch them at the warning signs, as I'm asleep! My last one of these was last Sunday. I woke at about 5am, with my hand going berzerk (tingly/numbness). Between getting downstairs for drugs and getting back into bed, my face and speech had gone. I woke about 8, and apart from the residual headache, and drunkeness, all was good.
I have 4 CT scans, and several overnight stays in hospital for pain control and rehydration now. Curiously, they seem to be mostly seasonal - From February to June I have loads, the rest of the year, I'll have very few. Which reminds me, I need to get to the quacks for more nasal spray!