Alright
Corners, free kicks, long throws, penalties
What Ich said about these, I assume indirect free-kicks also use the free kicks stat. I'd guess passing helps with corners and free-kicks that are crossed in as does crossing. Penalties seems strongly linked to finishing/composure and maybe a hidden attribute. Does strength affect long throws? I don't know
Crossing
How well a player can cross the ball?
Linked to passing/creativity/decisions
Dribbling
This combined with technique is what I'd describe as a players ball control skill after the first touch.
First touch
How well a player controls the ball at first. More noticeable on long balls and direct play. I guess this is important if you want your team playing fluid football
Heading
How accurate the players heading is. Possibly composure comes into play on a header at goal.
Passing
self explanatory, creativity + flair probably influence how extravagant the player is with his passes and how much risk he takes
Tackling
Accuracy of tackling? Aggression always helps and bravery helps with the 50-50's. Strength is also useful
Marking
How well a player can execute his marking orders. How well a player sticks with his man when man marking etc
Technique
A somewhat all encompassing attribute. How gifted your player is with a football, how well h strikes it etc
Aggression
Strongly linked with bravery. A player with high aggression will look to get stuck into tackles even when it's not always the best idea.
Anticipation
How well a player sees the pass coming. I think a good example is when clearing a corner towards your forwards. A player with good anticipation will react quickly and start moving to the ball quicker. This will affect how many interceptions players make during the match.
Composure
Only ever heard people associate this attribute with finishing, however I'd not be surprised if it also affects whether the player is comfortable on the ball under pressure. Players with low composure may be hurried unnecessarily and pass poorly or make terrible decisions.
Creativity
Affects a players ability to see that through ball is possible ahead of him. I would typically say that a player with high creativity rarely passes the ball backwards. Also highly creative players love the little balls round the corner.
Decisions
Going on from the last one, is the through ball realistic? Or should you make the safer play. I guess I'd associate this with player intelligence.
Determination
Could almost be renamed 'ambition'. I assume this reflects how hard a player will try in training to improve. Also might work with bravery/aggression/anticipation is some ways.
Work rate
Usually high work rate is backed up by high teamwork. A high stat reflects someone who will chase a long ball they are 2nd favourite to get.
Flair
One of the old footy games described this stat as 'player ego'. I guess a better word is confidence or overconfidence in their ability. Seems important on anyone you want to be dribbling past 2-3 players.
Influence
How much effect this player has on his teammates. A captain with very high influence should be able to improve the performance of players around him and also maybe encourage them to work harder.
Off the ball
Important for virtually every player who isn't a goalkeeper or central defender. Ichabod explains it well
Positioning
Does a defender play someone onside when the rest of the defence is pushed up? Does the player adjust position when needed?
Teamwork
derp?
Corners, free kicks, long throws, penalties
What Ich said about these, I assume indirect free-kicks also use the free kicks stat. I'd guess passing helps with corners and free-kicks that are crossed in as does crossing. Penalties seems strongly linked to finishing/composure and maybe a hidden attribute. Does strength affect long throws? I don't know
Crossing
How well a player can cross the ball?

Linked to passing/creativity/decisions
Dribbling
This combined with technique is what I'd describe as a players ball control skill after the first touch.
First touch
How well a player controls the ball at first. More noticeable on long balls and direct play. I guess this is important if you want your team playing fluid football
Heading
How accurate the players heading is. Possibly composure comes into play on a header at goal.
Passing
self explanatory, creativity + flair probably influence how extravagant the player is with his passes and how much risk he takes
Tackling
Accuracy of tackling? Aggression always helps and bravery helps with the 50-50's. Strength is also useful
Marking
How well a player can execute his marking orders. How well a player sticks with his man when man marking etc
Technique
A somewhat all encompassing attribute. How gifted your player is with a football, how well h strikes it etc
Aggression
Strongly linked with bravery. A player with high aggression will look to get stuck into tackles even when it's not always the best idea.
Anticipation
How well a player sees the pass coming. I think a good example is when clearing a corner towards your forwards. A player with good anticipation will react quickly and start moving to the ball quicker. This will affect how many interceptions players make during the match.
Composure
Only ever heard people associate this attribute with finishing, however I'd not be surprised if it also affects whether the player is comfortable on the ball under pressure. Players with low composure may be hurried unnecessarily and pass poorly or make terrible decisions.
Creativity
Affects a players ability to see that through ball is possible ahead of him. I would typically say that a player with high creativity rarely passes the ball backwards. Also highly creative players love the little balls round the corner.
Decisions
Going on from the last one, is the through ball realistic? Or should you make the safer play. I guess I'd associate this with player intelligence.
Determination
Could almost be renamed 'ambition'. I assume this reflects how hard a player will try in training to improve. Also might work with bravery/aggression/anticipation is some ways.
Work rate
Usually high work rate is backed up by high teamwork. A high stat reflects someone who will chase a long ball they are 2nd favourite to get.
Flair
One of the old footy games described this stat as 'player ego'. I guess a better word is confidence or overconfidence in their ability. Seems important on anyone you want to be dribbling past 2-3 players.
Influence
How much effect this player has on his teammates. A captain with very high influence should be able to improve the performance of players around him and also maybe encourage them to work harder.
Off the ball
Important for virtually every player who isn't a goalkeeper or central defender. Ichabod explains it well
Positioning
Does a defender play someone onside when the rest of the defence is pushed up? Does the player adjust position when needed?
Teamwork
derp?
"We are open to all opinions as long as they are the same as ours."