Thanks for all the input. but I have a few questions. In P:M it seems shorthopping is kind of obselete when it comes to Ness because his jjc seems to be a lot easier and closer to the ground, am I right or am i just bad at shorthopping? also it looks like l-canceling doesn't change my lag. Do I just suck at l-canceling too?
Short-hopping doesn't immediately become obsolete because a character has double jump cancel. Ness is a character who is naturally reliant on the technique, yes, but that does not abandon his improvements in the neutral as well.
Double Jump Canceling is both a gift and a curse. If you use the technique blindly, it will cost you your stock or put you in a huge deficit.
I would say to use it sparingly and use it when you feel its appropriate.
Referencing rising aerials from Brawl, Ness can maneuver himself in more ways than he used to.
Short-hop retreating fair makes a great wall and pushes the opponent back (and if I recall, has some deflecting properties on items like waddles and bombs).
Rising uair is wonderful. You can get two to three reps usually, and the delay of the move itself when rising makes forth an excellent finish.
i.e. DJC Dair at an appropriate % based on the character and rising uair. If you haven't been doing something like this already, I completely recommend it.
With L-canceling, you have the option of using either trigger button. In PM, the character flashes white when you have done so successfully. I do not recite when you are unable to L-cancel and for that, I would refer to Gmaster.
In my case, I don't use either trigger button. I use Z simply because it's there and available for me to use reliably and consistently continue my string of double jump cancels. Unfortunately, it also shares the grab/shield button so I have to be careful upon execution or else I might get something I don't want.
But other than that, some of the other tips in the thread will help you out.
PK Flash is a wicked offstage kill move and an anti-air. I recommend experimenting your opponents reactions in the air and adjusting to them accordingly.
Try wavebouncing it.
If you aren't already proficient in spacing, take time to get used to the tipper. I was told the length of it is 2 Ness', however I don't think about this at all. I kind of know its length after a year or two of playing the character.
Yo-yos are cool. They make for great tricks and juggles. Juggling fast-fallers with usmash can be pretty fun, but I wouldn't limit yourself to just fast-fallers. Characters with bad techrolls are also subject to this move. As noted, yo-yos can be quite useful for tech chasing. Yo-yos are also pretty nice for edge-guarding as well, but don't limit yourself to one yo-yo move. I would use both despite that you might get an idea that usmash is more applicable than dsmash You would be very surprised...
As choknater stated, PK Fire is extremely useful considering that it covers up the lack of range in the neutral and activates on shield, making it an auto-pressure tool.
I recommend trying out different methods to throwing it out in the neutral.
Maybe some...
Grounded PK Fire
Aerial PK Fire
DJ PK Fire
DJC PK Fire
Wavebounce PK Fire
Well, at least those are the ones that come off the top of my head. And I'm actually somewhat disappointed with the suggestions, none of which discuss the overall importance of PK Thunder. There are a numerous amount of ways to hit yourself with PK Thunder. For example, if you hit yourself with the bolt on the top of your head while on the ground, it puts Ness in knockdown state. So what can you do with this? You're essentially putting yourself at a disadvantage by doing something like that and I've only ever used it for mindgames. You can grab a couple of invincible frames if you decide to get-up attack, but you also have the option of rolling either direction or getting up normally (which I believe the last option does give you invincible frames as well, and is often forgotten). The tendency of newer players from what I've noticed is that they rely on the basics to move around. They aren't confident in themselves when they see a guy performing a wavedash or a waveland and often become intimidated. I'm not saying that your case is the same from what I've experienced, but if you're able to use every movement mechanic sparingly, you'll benefit greatly from knowing that these options are there and you're not limiting yourself to anything ever.
I'm not sure if it's the same here, but in Brawl, PK Thunder has infinite priority. Why is that important? Because it can help you out just by knowing about it. You can deflect stuff and play pseudo footsies with your opponents to potentially provoke them and get the upper hand. But the real reason I brought this up is because most people who pick up Ness forget the essentials of recovering. Yes, that's right, recovery. Ness' recovery is one of the few factors that may very well outweigh his pros.
In that interval, so much can happen.
For example...
You PK Thunder offstage on the left side of Metal Cavern, not too low, but you're at a 55 degree angle or something specific. Let's say you're playing a Falcon and he wants to offstage knee you (for whatever reason). He intercepts the bolt immediately as it comes out of your head and he gets to rebound while you're stuck eating the dirt. This could very well happen anywhere and at anytime.
So what can you do here?
Well, you can delay PK Thunder and fix yourself in a moderately safer position. It isn't much, but it's definitely better than having someone kamikaze your bolt.
Depending on the stage, the way you scale the wall will vary on the distance you shall receive. But something that I don't see many Ness players fancy well or at all, is maneuvering the bolt WHILE suspended in the air in a scenario like that to deceive their opponent (there used to be a diagram that Kink-Link5 had which illustrated some other ways to maneuver the bolt and hit yourself in the desired direction). I'm a victim of that. I believe since Ness' recovery as greatly been improved, it can throw out the idea that perhaps this is too practical.
As a Ness main, anything practical is of use. It's not something to forget. With that being said,
I would focus on
mastering PK Thunder first. It is by far his most important move in my honest opinion. Some are likely differ in opinion, but I feel that if you don't master this move, you are leaving a giant opening in balancing yourself as a Ness player.
That's pretty much anything I can think of off the top of my head. Of course I didn't want to get too complex with the tips, so I just threw out some things you might want to experiment with. I recommend you watch all the Ness' you can. It's always good to engineer new styles while trying to find where you stand with the character.
Oh! There's been talk about LDJC or Ledge-Jump Double-Jump-Cancel. It's actually a very precise input and it does have its practical uses. I recommend you give it some consideration.