You should go to
http://www.irs.gov/publications/p463/index.htmlThen start digging up records of your work related travel.
If you deduct mileage, depreciation is already figured into the mileage rate, so you can't deduct both. You can deduct the miles you drove from your home to the temporary location and back, also the miles you drove for business purposes while at the temporary location.
If you got per diem, you can't write off living expenses unless you have receipts that total MORE than you got for per diem. You can deduct the difference. You CAN NOT deduct the difference between your per diem and the GSA rate. That is what we call a "turbine myth" at work. It has triggered many many audits.
You can deduct the cost of having your laundry done while away from home.
You can also deduct union dues, work boots, safety equipment, tools, supplies, training fees, license fees, and the cost of any trips that you had to make to go home periodically (around once per month) to take care of your personal affairs. You will need records to prove all of these things.