Having played Lucario plenty of times by now, I would not recommend Lucario to new players. His A moves are tricky to understand at first because of the displacement of hitboxes between his limbs and the Aura he projects. Like with his dair, you must hit a little below the foot, NOT with the foot, to get the full effect of the attack, and the same goes for his A-button comboes. if you are too close, your attacks will not do too much or will miss entirely, but if you're too far then you're screwed also.
His Aura ability isn't that easy to exploit, either; You don't start seeing real results until you go past 100% in damage, and by that time you are vulnerable to death from a smash attack in the right environment/character attacking you. And since your attacks are fairly weak at the start a new player with no strategy will not excel. Not to mention there are many factors to his special attacks that need to be taken into account(how his Double Team and Force Palm work depending on the different situation, and of course the effects of Aura). Lucario is definitely not a newbie-friendly character.
For me, the key to taking advantage of his Aura was taking advantage of the fact that while all his moves are weak at first, they still have good stun and knockback, and his regular combo is a great starter because it's quick. His smash moves have delays which is both good(fake out opponents who dodge prematurely) and bad(slow smashes compared to others, like Pikachu, who can do ALOT of damage really fast). So by doing as much damage as you can as quickly as you can, by the time your opponent has started dealing damage to you, your attacks will be hitting them much harder.
That's my two cents anyway. Lucario is not newbie-friendly.