You're going to miss the joys of wiping your increasingly squirmy toddler's behind, and getting used to the extra cash you'll have in the post-diaper era can be tricky too. In all seriousness, potty-training gives both you and your toddler some freedoms, but it can be a hugely stressful process. Hanging checklists in your bathroom helps you maintain consistency. Relaxing and being patient will help your toddler make the transition more smoothly.
If only each toddler was equipped with a switch that, once flipped, meant he was ready to potty-train. No such luck, so you'll have to use your judgment to determine when he's ready. A child who is ready should show some interest in using the toilet and wearing underwear. He should be able to follow directions and pull his own pants up and down. His toilet habits should be fairly predictable; his bowel movements should come around the same time each day and he should be able to hold his urine for at least a few hours. If he fits all or most of these criteria, you can start introducing the big bad potty.
You'll need to make a trip to the store before beginning potty training. Your toddler only needs to fall through the opening of your toilet once in order to traumatize him for months, so a child's potty is a must. Buy a potty seat, which fits onto your toilet, for when he's ready to transition to the real thing. Let your child help pick out these items, plus a wide selection of underwear decorated with his favorite characters. Replace his tab diapers with pull-up varieties. Pick out children's books about using the toilet, choose a few small toys he can play with while he's sitting in the bathroom and get some stickers you can use to make a potty chart for him. Hang a piece of paper at eye level to the potty and explain that you'll add a sticker each time he "goes."
Use your acting skills to make the potty seem like the most exciting, big-kids-only item in the world. Encourage, but don't order, your child to sit on the potty a few times a day, especially before and after sleep and about 15 minutes after he eats. Stay with him, reading a story or singing him songs, while he sits for a few minutes, and praise him heavily after each attempt. It could be weeks before he manages to put anything in the toilet, but keep these potty breaks a part of your daily routine. When he does go, make a huge show of your pride in him. He'll need help wiping for many months after he starts training, though a girl can more quickly learn to wipe herself after urinating. Let a boy sit for all business until he's transitioned to using the big toilet. After he goes, help him transfer his business into the toilet and flush it. Encourage your child to wash his hands after each trip to the bathroom.
After a few weeks or months of your toddler using the potty, it's time to lose the diapers altogether. Let him wear underwear for several waking hours each day while he's at home, but continue putting pull-ups on him for school and sleep. Remind him to use the toilet every hour or so, and clean up any accidents with a smile instead of anger or irritation. At this point you can start encouraging him to use the potty seat, if he's not already. If at any point he consistently refuses to sit on the potty or seems generally resistant to the process, switch him back to pull-ups full time and give him a break from the potty game for a few weeks. He'll get the hang of it eventually, and you won't be sending him off to college still in diapers.