My son is a great sleeper, compared to my daughter who did the every few hours thing till I weaned her at 12 months.
Son was sleeping a solid 5 hour stretched by week 2, by week 4, he was up to 6-8. I really don't think it had anything to do with me. He just was a better sleeper to start with. So, that's number one: each kid is different. Some really do need to eat every few hours, others don't.
Unlike with my daughter, however, I moved my son out of the bassinet in our room into his crib in his room at 7 weeks. He was keeping ME up with his noises. That's one thing I totally did differently this time: I would let him make his noises, I would only go to him when he would cry. Giving him time to resettled truly helped.
A few other things I did differently starting around week 10 or 11 (when the the nature of their sleep changes): I didn't nurse before putting him down. I separated the nursing out from the sleep, so I'd nurse, and then we'd read our book, for instance, and then he'd go into the crib. I always made sure he had his eyes as wide open as they could be.
A few other key differences I did AFTER week 12:
1. If he would wake, I didn't assume he needed to be nursed. I would check his diaper and rock him, seeing if he'd go back down without eating. Since eating in the night does become a habit, I'd only nurse if he really needed it. And there is a difference between needing food and nursing for comfort. I learned this time to use other ways to comfort my baby.
2. When we did create a bad nursing habit during the 4 month growth spurt, I used the Baby Whisperer shh and pat method to break him of his night wakings. Once I got him to stop waking from his first waking, he settled into a good 8-9 hour stretch. It took a few weeks, some really painful nights, but by 6 months, he was back to only waking once a night.
3. And now at 7 months, he still only wake once a night and I am very, very happy with this. Sure, there are people who would say he could be doing 12 hours, but he slept 13 hours last night. I know he would have been up much earlier if I didn't feed him at 3.
4. He takes two terrific naps: we have a solid routine. In fact, that is one thing I did very differently this time. I.5 hours after waking, I would change his diaper and put him back to bed. By month 3, he had a solid routine. I even woke him in the morning to make sure he stuck to his routine (never letting him sleep more than 15 minutes pass his usual waking time). This routine has been terrific. He naps for 1.15 minutes every morning and 1.5 hours every afternoon, and he sleeps 12-13 hours every night. My daughter maybe would get a grand total of 11 hours of sleep. I don't know how much of it was her and how much of it was me, but I can tell you that I didn't try to put her on a schedule, I watched her. I didn't watch my son, I just assumed he would be yawning soon and I'd get him ready for bed. By doing this, I rarely missed his sleep window, and by 4 months he was able to put himself to sleep with no problem! By month 5, he'd go back to sleep on voice command.
Hope this helps some. The key thing to keep in mind, I think, is this: a little pain early on lessens the overall pain. There were a bunch of nights I held a screaming baby who was protesting me not giving him my boob, when, I knew damn well he didn't need it, as he just ate 1.5 hours before hand, and he usually went 5 or 6 without food with no problem! But, those few sleepless nights were so worth it. I get a good 5 hour block of sleep before he wakes me every night. Unheard of, unthinkable, with my daughter.
Don't worry about it, really, you will quickly realize how different you parent with the second child. It's amazing, really.