http://forums.bimmerforums.com/forum/showthread.php?1579870-E90-DIY-Headlight-Adjustment-Alignment
There you go, did mine myself. Huge improvement.
It's quite hard to see a difference while adjusting slightly but mine were extremely low to begin with.
Get it as high as possible without blinding cars.
If you have xenons with a clean cutoff you can see the line of where the light stops.
That line should be below oncoming traffic's windscreen
For cars in front of you, keep it below the top of the boot (& side mirrors).
Halogens allow you to slightly adjust height from inside the car as well (not sure if xenons can do this, think they have auto adjustment?)
Useful for when you're driving in a dark area & you don't want to use your brights but you need to see further ahead.
If some of my advice is a bit off, feel free to rip me apart :flyfun: