For A8, you can rise your coding skills , with any free 3D models, you can even found a lot in Acknex unlimited site or free ones in TurboSquid for example !
To improve your modeling and texturing , you can post on forums like Polycount.net, gameartisans.net , 3Dtotal.com, if you ask for critiques advices, lot of people can help you ) !
Before joining a team try to finished before some littles games using your 3D art ! find a game you like , for example Megaman; make it 3D with a Third person camera, with ennemies and levels ! It's just an example !
The better way to improve is PRACTICE A LOT , MAKE ERRORS, MAKE BAD LITTLE GAMES FIRST , AND HARD WORK
So don't hesitate make your own mini games, you'll improve 3D art and A8 code( lot of people can help you here) !
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Another way, find people that are also beginners and find together an idea of game , without targetting too hight !
Juts my personnal advices !