use the c stick to perform your smash attacks if u use a gamecube controller, its faster then the side A+control stick move
It seems that most Lucas mains B-stick for the easy ATs and the improved recovery options. If your a lucas and you c-stick, it probably is for improved aerial game and movement, not specifically for smashes.
Ness has his back throw. Lucas has his down throw. Both can KO.
Lucas' throw game is decent at best. Our D-throw is ok, but it doesnt belong anywhere in the same sentence as Ness' B-throw (best/strongest in game). The best thing about Lucas' grabs/throws is his pummel, which doesnt even get much use. this is because if we manage to grab, we are probably pummelling once or twice, D-throw to U-tilt. Its not great- decent at best.
This question should have been asked in the Lucas boards, because we could have given you a more direct answer than other mains- however, I will answer it here.
If your having a problem KOing people at large percentages, you are probably staling your smash moves and not getting max damage out of them. You are also not using aerials enough (specifically use Nair to break shields and dair to rack up damage), and you probably are not gimping properly. Lucas has some of the best offstage gimping abilities in the game, as his projectiles allow him to put his opponent in danger without significant risk to self.
It is likely that you are using smashes to rack up damage, and then getting frustrated because you aren't KOing with the stale smashes. Saving your smash moves for KOs is pretty big- generally the exception to this is if you have a combo or your getting a free U-Smash. Obviously if you are getting a chance to get a free smash do it, but then wait until your smash is fresh again before going for a fully charged, KOing smash.
your biggest KO move is F-Smash, because it is quick, powerful, and has good knockback. D-Smash is more of a defensive move than a KO move, useful for punishing people who roll and spotdodge too often. U-Smash.... well you should use this very rarely and only when you think you have a good chance to hit. While U-Smash is crazy powerful, the ending lag of this move means if you miss your getting whacked. There is a specific thread on the Lucas boards discussing how to get a free U-Smash without significant risk to Lucas, I would consider reading it over.
As for gimping- as soon as your opponent leaves the stage, you need to immediatly consider how you will attack them. Often the best approach is to use PK Thunder or PK Freeze as a first line of defense, to prevent your opponent from coming back to stage without using an airdodge. For PK Thunder, make sure to loop it around your opponent, so even if they do airdodge, they are probably going to get hit. PK Fire is decent, but it doesnt have the range that his other special attacks do.
If you decide to go out and attack with Lucas, you need to first ensure that you can safely get back to stage- generally you dont want to be trading stock 1 for 1. Your dair is again probably your best damage-racking move(and has a soft spike that is amazing), bair is your best spike (learn the proper spacing for this, and practice lots!), nair hits for a decent amount and its last hit has some nice knockback, and uair.... well you probabally dont want to use uair. Fair is a typical fair, nothing great, but it can easily be chained for simple KOs.
Look at some Lucas threads, read up on simple combos, and practice lots. You didnt mention that your opponents are KOing you early, just that you are KOing them late- so I didnt go into that. If you have any more Lucas questions, throw them on the
Lucas General Discussion Thread- we will answer them. Additionally, if you want me to go more in-depth on anything I mentioned above, feel free to PM me
