http://www.glasgowsurvival.co.uk/
Good luck!
From the 'weapons' section of that site:
"Only a Glaswegian could come up with the hammer with a stanley knife taped to the top. Genius!"

Don't wear green in certain areas of the city,don't wear a cross round your neck and don't do anything that remotely looks like you're blessing yourself!
Alternatively,in other areas of the city dont wear a Union Jack t shirt,mention the Queen or wear blue.
And wherever you are,don't mention Norhern Ireland!