I’m surprised no one has mentioned it yet, but you might want to pick up a copy of Healthy Sleep Habits, Happy Child. He will give you some good tips on regularizing naps, as well as helping do the cry-it-out thing effectively.
Good luck!
I forgot to mention the best advice I was given. Never make it where it has to be dark and quiet for your kid to sleep. You won’t always have that luxury.
My daughter fell asleep on a field trip of kindergarteners. At a small aquarium. 50 5 year olds.
I can pretty much dangle her by her feet and she’ll sleep.
Best advice I ever got.
Yeah, but when you start the dangling, do you let her cry it out first? 
Ditto here. My son could sleep though WWIII
At two months I started to prepare my babies for bed. I gave them all the loving, hugs and kisses and then put them to bed. As long as I knew they were fed, dry and warm I didn’t worry about their crying to much. They will cry themselves out. It make take longer as it sounds like your child has never fallen asleep in his crib on his own.
I would think at least one day time nap is a good idea. I know if my kids missed naps they would be over tired and had a harder time falling asleep at night.
At that age they should start sleeping through the night or at least most of it. It sounds if he is eating two to three times a night then maybe the cereal is a good idea. I started both of mine on it around three to four months.
I think setting the example now is the best way. It made it easier when they got older to understand bed time meant bed time. They did not fight me to much when they got older and fell asleep fairly quickly or at least played quiet in bed until they just fell asleep.
There are always rough nights, that is normal and every baby is different.
I think if I had to still get up two to three times a night after four and half months I would have been a zombie.
This is the best advice I got as well. Leave the TV or radio on. Wash dishes or run dishwasher. Wash a load of clothes or run the dryer. Hell vacuum if you think you can get away with it.
Do not tip toe around. Make all the normal noises you would make as though there was no baby asleep.
Both of my kids can sleep anywhere and are sound sleepers.
Is that because your kids were always good sleepers, though, or do you think it was because of that extra effort to get them used to sounds?
I ask because as a baby, I was a very light sleeper. My parents said they had problems getting me to sleep until they finally just let me sleep in my own room. That way I wasn’t waking up every time someone walked into the room. I’m still a light sleeper, generally. I don’t think I can sleep anywhere, but I’m usually good about getting back to sleep.
Mine, too! He slept through an entire Bat Mitzvah, the lucky guy, then conked out again while the big band started during the reception. Amazing.
It’s going to take a conscious effort for me not to keep everything silent at night. We’re in a tiny house, and I find myself tip-toeing when I’m two rooms away. I also find myself cringing in fear when my wife does the dishes one room away from the sleeping baby, or when I have to flush the toilet, which is about 6 feet (and one closed door) away from the crib. On the other hand, last weekend I had him in a Bjorn (front-carrier) and had some music cranked up (not too high…) and was bouncing him around to the music…and he surprised me by falling asleep somewhere between Man of Constant Sorrow and Van Halen’s Ice Cream Man. I had no idea he could fall asleep during such a ruckus, but I guess I learn something new every day. 
FWIW the book my wife and I read before our oldest was born said this about bedtimes and noise.
"If your baby’s bedtime is 6 PM do not go tiptoeing around and whispering. At 6:05 you should have the stereo blasting, and the dishwasher running. Let them fall asleep with the noise, they will learn to sleep despite it.
When we brought our oldest home from the hospital, the first night must have been 15 minutes of straight crying. (he was fed, changed, and swaddled)
The second night was maybe 5 minutes
The third night was Waaaa…snore. It was like that from then on. By the time he was 5 weeks old he was sleeping though the night.
What book was that? A 5 week old is waaaaaaaay too young to be sleeping through the night without eating. I wonder what their definition of “through the night” is.
Hey if the kid woke up we fed him. If he didn’t wake up, I sure as hell was not about to go wake him up to feed him. Are you nuts? A sleeping baby is a good baby. 
When my son (now 29) comes over tomorrow I will make sure to tell him he slept though the night way too young.
BTW the book was called Baby Taming. Excellent read for a first time parent.
My son was not a good sleeper when he was born. He was born six weeks early and only 5lb 14oz. He ate every two hours and he had colic so it was not easy for him or I to sleep. There were times I would just get him down and start creeping out of the room and he would wake again. I would tip toe around because I was so tired I just wanted a half hour or an hour of rest. Any noise made me cringe and more than half the time would wake him up.
When he got about two to three months he was eating more so the feedings were less often so he started sleeping better but the “every two hour wake” was still there even though he was not hungry. I had to learn not to rush in at the first crack of a cry. More often than not he would fall back asleep again in five to ten minutes.
Since I had more time and was getting more rest I started turning on the TV or leaving it on when I put him down. I did dishes and laundry and he slept right through the noise.
If you think about it, a baby is going to hear “mom and dad” easier if there is less noise. A TV or radio actually mask the noise. If they get used to these noises then I think they are more likely to sleep through them. If is always quiet then every “strange” noise is going to alert them that something is going on.
A TV, radio, dishwasher, toilet flushing etc. are not “strange” noises, they are normal household events.
He is a good sleeper now, sometimes to good. Once in awhile he will sleep over and he sleeps on the couch. I can come down in the morning, let the dogs out, make coffee and turn the TV on that is five feet from the couch and he sleeps right through it.
My daughter was the opposite. She was a good sleeper from the beginning. She was a happy and easy going baby. The noises of the household and the fact that she had a two year old baby brother were noises that she was used to since the first day home. They were not “strange” to her so there was no reason that she would be alerted and awakened by them.
It is really not an “extra effort”. They are normal noises. Why would we try to hide them from them?
I wasn’t so lucky but I have friends that were. Their pediatricians all said the same thing “long as baby is growing and gaining weight, long as baby is alert when awake, count your blessings.” (“Through the night” is generally defined as six hours or so by pediatricians - but its usually a parental description).
It is suppose to be quiet at night. I don’t suggest banging pans at 2am.
We had a tiny house too. Our bedroom door, the babys room door and the bathroom door were all right on top of each other.
As I said above. There is no reason ot hide the normal household noises from him. He is going to hear them his entire life.
I can’t tell you how many times my kids fell asleep under the strangest conditions. I did learn though if they are asleep to leave them be.
I used to get frustrated when I would drive home from my moms and my son would fall asleep in the car seat. I would carry him in and try to lay him down in the crib and he would wake up everytime. Then my mother asked why I was not just detatching the carry seat from the carseat base and then carrying it in with him asleep and just set it in his crib?
Dah, I never thought of that. So from then on I did just that that when he fell asleep. I had a sleeping child for at least another hour or two. He just slept in his chair. For all he knew he was still in the car.
I think we just have to remember that every child is different and you have to find out what works best for your baby but do try and take advice from all angles and see what works best. It may not be one single method but a combination of them.
My daughter was like that at six weeks and yes it was five to six hours. It was a like a god send compared to her brother that did not sleep that long until three months.