longest joint ive smoked(that was with 2 people, passing regularly and taking puffs every 10 seconds or so) was about ... 10 minutes. That was with a normal king size paper and like, a gram of weed, maybe a lil less. Theres no way a joint, thats being smoked often can last more than like, 10-15 minutes unless your taking really tiny hits and taking puffs every 30 seconds or some shit.
Best way to roll a joint? Practice, practice, practice. Its different for everyone, theres no one perfect technique. Just a few things that will make a joint easier to roll and more even to smoke(and look).
1: grind your weed up real good, chunky is not good.
2: make sure it is evenly distributed
3: when initally rolling paper, make sure its not 'folding' in parts and that it is going under/against the weed, this makes it burn even.
4: make sure you lick it good, i mean, make sure theres plenty of juices on it(not too much tho!)
5: tight is always better than loose
6: pinching and twisting the end to make it into a point means you dont waste any weed torching/lighting it, and it starts the joint smoking evenly.