I've got three kids (Haley 10, Jake 5, Keegan - 20 months) - I'm a sucker for punishment
Each of my kids if very different and responds in different ways to the same situation, no one can really tell you how to parent because of this - generally speaking I've found only a few 'norms' which help with 'managing' my brood:
(1) Attention, all kids love attention and one on ones
(2) Distraction, especially at an early age, if they throw a wobbly then ignore it and change the subject - kids under 8 tend to be easy to manipulate, you can see a temper tantrum coming over him wanting sweets - ask if he wants to play game 'x' with you ... if its something he likes then there's a good chance his brain will switch over to that and forget all about the sweets.
(3) Don't get riled, I find that because I'm fairly laid back my kids won't bother screaming and shouting with me - they know I'll sit there and wait for them to calm down before talking to them (with prompts of 'When you've calmed down we'll discuss this' generally thrown in).
(4) Routine, this has generally helped - although less with some of the kids than others.
(5) Ignoring them if they're misbehaving, Haley went through a stage of throwing temper tantrums in public when she was around 5 - it stopped abruptly when I took her outside of a Pizza Hut screaming at the top of her lungs, we stood on the sidewalk for 10 minutes with her in my arms kicking and screaming while I stood there refusing to look embaressed. After 10 minutes she asked "why everyone is staring at us" and I told her simply that they thought she was acting like a wally ... after that she got rather embaressed calmed down and asked to go back inside, she hasn't thrown a public wobbly since.
NB. It helps if you're immune to embarressment, my kids know NOTHING can embaress me and that I have a warped sense of humour, my favourite way of keeping Haley on the straight and narrow at the moment if she starts acting a brat while I'm walking to school is to ask her sweetly "Would you like it if I pick you up in my arms and carry you cradled like a baby into the playground before giving you a kiss goodbye" ... she's never called me on it (and I don't know if I'd actually do it) and normally snaps into line instantly.
(6) Accept if you're playing games with them its 'their' game and not yours, I found this hard initially as I used to play 'cars' for example in a very different way to Jake - but hey he's the kid not me, roll with it.
If you think any of the above makes sense and you haven't tried it then give it a go, if not then feel free to ignore them - as I said at the start every kids different and only their parent really knows how they tick.
The hardest age is the around 2-3 mark imho, they're big enough to get into trouble, but small enough that you can't effectively reason with them.
It also gets harder the more you have, when you've one its fairly 'easy' as the parents outnumber the kids so giving them 1 on 1 is easy, when you've two you tend to find yourself passing them between yourselves (especially if there's an age gap and they have very different interests) ... when there's 3 its mayhem as they can get fairly jealous because its impossible for all of them to have 1 on 1 at once.
That being said, being a parent is wonderful and my kids bring me a huge amount of pleasure - I wouldn't swap them for anything.
One of the hardest things for me to come to terms with is Haley becoming increasingly independant now she's 10, although it is fairly cool that both her and Jake are now better at 'twitch' action games than I am - its great to have people on tap who can get me through the hard bits
PS. Do your best to ignore any dirty looks you get if your kids are acting up while you're out and about, most people who aren't tolerant haven't been parents themselves (or have forgotten what its like) - just do the best you can.
Finally if your kid is tall for his age then peoples reactions are generally harsher imho - for instance Keegan is only 20 months old and is around the heght and build of a 3-4 year old (hey I'm 6'6'' myself) - this means most people who don't know him think he's acting very very immature and brattish, he isn't - he's just a normal 20 month old. He walks, can talk a little (when he wants to) and generally heads towards trouble as fast as his little legs can take him, it doesn't help that he's a trainee escapeologist and can get out of any Pram harness in under 5 seconds should your attention wander off him.