When installing any lock for the first time, ensure you read the installation instructions. Many warranties are void with incorrect installation.
Select the correct tools for the job. Having the right type of screwdriver for the type of screws, sharp drill bits of the correct size, sharp chisels etc, all make the job go easier.
Mark the correct measurements before starting to drill.
Check the backset measurement (the distance from the edge of the door to the centre of the lock cylinder or key hole).
Check that the rear of lock body will clear any glass in the door.
Check that no wood chips or metal filings get inside the lock body or latch assembly, which could cause the lock to fail.
Do not overtighten any fixing screws.
When installing any additional hardware to aluminium windows, first check how the existing window catches / handles are fixed.Generally they are either Face Fixed or Sub Fixed, and this will indicate how the additional fitting should be attached.
When drilling over glass either fit a "sleeve" over the drill bit that only allows it to just penetrate the aluminium or carefully drill a small pilot hole and then use a nail to locate the glass which will help you judge how far you can safely drill. There is nothing that flattens an installers ego more than the sound of cracking glass.
Most manufacturers do not include screws or rivets with locks / stays for aluminium windows due to different sizes being required for different types and applications.