I've been battling the little buggers for half a century. Here's what I've learned.
Take them seriously!
Most of the time they're only a minor irritant, but at their worst they're very nasty. I've twice had to help people in toxic shock from midge attack. Make sure you're prepared.
Know your enemy
They don't like sunlight, so are are more active at dawn and dusk, in shade and on overcast days.
The higher the humidity the more active they become, and they can fly in light rain. They become inactive when humidity falls below 60% or so.
The population falls away rapidly above 700m (2300 ft)or so.
They can't fly in wind speeds above 6mph (10kph), but can still get you on breezy days if you take shelter.
They can't bite through clothing, but they will crawl through any gaps in your defences.
Take avoiding action
Avoid the crowds!: intensity varies from place to place and from season to season. Use the Smidge Midge Forecast to avoid the worst areas - not 100% accurate but still pretty useful.
Cover up: when things get bad, no repellent will keep them all off. Carry a broad-brimmed hat and headnet, some light liner gloves and full-coverage clothing.
Defend your living space: a tent with full insect netting is essential. They can get through mosquito netting - you need the finer midge/noseeum netting. In bad conditions it's impossible to avoid carrying dozens of midges into your tent on your clothing. The easiest way to deal with them is to burn mosquito coils for a few minutes - you can get holders that reduce the fire risk.
Use insect repellent: DEET is the most effective for most, but quite unpleasant and toxic. So you might consider the alternatives.
Personally, during midge season I like to head for the ridges and plateaus and camp high. Though provided you steer clear of the worst areas you shouldn't have too many problems, even in the valleys. But prepare for the worst or you could end up in trouble.