I too am vary young and i have a fairly hardcore rig.  just cuz your young dosn't mean you can't do somthing.  anyway,  i will take a guess and say you have a sammy.  The easyest way to lift them is a Spring over axle lift.  you get about 5 inchs of lift from that.  some more ways to gey more lift is a body lift or lifted springs. as for tire i don't know what size but for your useage i would go with a M/T tire.  you will soon be piss that you sammy only has about 60 squirrel power so you will want to upgrade engines from a 1.3 to a 1.6.  gears and locker will come after that and so on.  hope i helped.  lata stu