At our hotel I picked up the latest issue of the free "Time Out - Doha" magazine. It is a good resource for information about restaurants, nightlife, shopping, things to do and places to see.
Apart from that the magazine usually features some interesting articles about the local life, the city and even more.
Luggage and bags:
Bring durable baggage as you do not want it breaking and bursting when you arrive. There are plenty of people to help you out at the baggage reclaim.
Clothing/Shoes/Weather Gear: It is HOT in the summer! Light weight clothes are ideal. In the winter it does tend to rain for a week or so in December and can be quite cool at night. Pants and short sleeves are comfortable during the day, if not the use of shorts.
Toiletries and Medical Supplies: You can get most any type of supplies in Qatar, especially Doha that you could find at home. But always bring extra just in case you think you may not be able to find what you need.
Photo Equipment: It can be quite bright in Qatar with not too much to block the rays off the sand. Sand storms can be regular at the end of winter so be mindful of expensive equipment. I brought my digital camera with me and it worked just fine. Though some filters may be nice to have.