You don't want to be stuck in the middle of nowhere unprepared. Always take water, money, an extra layer, tool kit, puncture repair kit, extra tube, pump, shades or glasses, a mobile phone and a snack.
Learn how to Service and maintain your own bike(s), you can't always rely on your LBS to get it right. Avoid Dumfries Cycle Paths, they're littered with glass and other nasty stuff. The red cycle lanes on the side of the road can sometimes be dangerous. You aren't obliged to use this lane, so if you feel safer in the traffic lane, use it. Watch out for pot-holes and beware - sometimes puddles conceal them. Never assume a motorist sees you, make eye contact with them at junctions and make sure they spot you. Cycle confidently, and be courteous to all road users...including taxi and bus drivers :-)