Many ways to skin a cat, but as an attempt at finding some generalized truth:
- Ability to score: Pure finishing and shooting.
- Ability to get chances to score: Movement, dribbling/skills and physical ability.
- Ability to create chances for others: Technical ability, creativity, physical.
- Ability to partake in buildup play and defensive play. Size, skill, pace, work rate etc.
Finishing ability without the ability to get into a lot of scoring chances and do stuff for others won't get you all that far (Bent perhaps?). Just like creating chances for others and working hard for the team won't make you a top striker (Crouch). At the very least you need finishing/shooting ability and good ways to get into scoring chances yourself and/or create them for others. Most of the best strikers will score highly on at least 3 out of 4 of those I think.