hi!
there is trouble in maya viewport with alpha.To avoid them, assign new material to geometry with alpha, so in viewport there no be those artifacts. In the end there will be 2 materials on this tank with and with out alpha.
about texture i can say that it looks painted.
-avoid of using solid white lines on the edges they need to be non regular. stronger near the cornes, and week in the middle
-there is no dirt on your tank.
-where is damage? scrathes, rust, maybe peeling paint(some where)
-all metal is green. make some small metal parts darker or even black so this details add points of interest.
-metal need color variation add something like that(
http://cgtextures.com/texview.php?id...55676223c14475) on the metal with 5 -10% transperancy with overlay or color
-rivets look cloned? to avoid this erase (with ~30% transperancy erase tool) some of them.
-pay attantion on small details(rivets, lockers, metal seams)
Обои рабочего стола · Техника · Военные · M1A1 Abrams Tank | Бесплатные фотообои 1024x768
http://www.historyofwar.org/Pictures/Centurion.jpg
http://www.enemyforces.net/tanks/centurion.jpg
PS If there grammatic mistakes in this text, well my english is not good

PPS Yes! those strange link is available to