Mike,
Some suggestions for a perfect walkaround:
Of course you should start from one point and then go around the vehicle taking photos of various parts. Remember that sometimes it is good idea to take two shots of a vehicle part - wide angle one and more zoomed one. The former shows the location of the part on the vehicle, the latter shows details of this part. Some more complex parts require a few shots from various angles to show all details.
Think of what areas are least likely to be well photographed on "general view" pictures available elsewhere and try to take good shots of them. Such areas include:
- bottom of the hull and the back side of wheels & suspension parts,
- all upper surfaces of the hull and turret (mainly turret! - VERY IMPORTANT as most photographers are not able to get on top of a vehicle),
- suspension parts: shocks, arms etc.,
- at least some basic interior shots - mainly what can be clearly seen through open hatches (periscopes, consoles etc.)
- some other hard to see areas, like turret ring and bottom of the turret and turret racks.
Try to locate some ID plate of the vehicle, which will show the exact model and serial number of photographed vehicle. Take picture of each marking you see on the vehicle: bumber numbers, registration numbers, national symbols, maintenance stencils, placards etc. Picture should show clearly the location of each marking.
Also remember about the barrel! I've seen a lot of walkarouns where photographer completely forgot about the barrel and did not include any pictures of muzzle brake and fume extractor.
Don't forget about a series of general views of the whole vehicle from all sides (if possible).
And have fun!

Pawel