OK. I went into a long list before of why Kirby is the worst character in Melee (although it has been decided that Pichu is now the worse), and if you are not shield grabbing alot with Kirby in Melee, then you are clearly playing him wrong. Kirby's entire game revolved around grabbing/ shieldgrabbing, f air/ bair, and dtilting to do damage (with the occassional uptilt comboes). For KOing it was usually f tilt/ fair/ bair/uair (usually after an uptilt on fastfallers), or gimping with dair/dtilt/dmsash/bair. If you were really good, then maybe you might get a a few upsmash kills, or a few ground hammer kills. You also might get the occasional kirbycides.
Reasons why he was so bad.
1. Terrible aerial control.
2. slow running speed
3. Low KO power compared to rest of characters (his powerful KO moves were also ridiculously hard to hit with because of really tiny sweetspots)
4. No aerial defense because of no aerial control, fall speed, no aerial attacks that were fast enough or with good enough priority to save him before he gets hit, only one aerial dodge which doesn't help because characters could attack twice before kirby could land and attack.
5. Light weight + he gets comboed very very easily because of hit stun, and no aerial defense= very easy character to KO.
6. Low range, priority, with stupid small sweetspots on several moves
7. No combo potential except for maybe uptilt comboes, d throw tech chase, and bair WOP if you were really good.
8. Too many moves had very small sweetspots or were just too slow/laggy
9. Opponent could get out of f and b throw whereas NO ONE else in the game you could get out of their grabs midthrow
10. Kirby loses ALL his jumps in any throw which means if you get hit out of any throw you are going to die.
11. His recovery move was way too slow and didn't spike, which means opponents could just recover before the move ends and punish you.
12. I almost forgot. Certain matchups were so one sided it was absolutely impossible to win if the opponent was a really good player. The matches that were the worse was Mario, Fox, Dr. Mario, Samus, Ganondorf. Then Matches that were nearly impossible but doable was like Jigglypuff, Peach (crouchcancel against Peach once and consider the match lost. It was difficult cause Kirby needed his d tilt), Falco (well he isn't that bad, but for every mistake you make you have to receive like 50-60 percent), then maybe Marth although it is the same situation as Falco.
I might be missing things but yea this should give you an idea.