If you want a line with all one All-star, release him from his NHL team, his All-star team, and his World All-star team--all before signing him to your team.
Avoid "one season wonders". For Season mode, a seemingly cheap price tag on a good, young player might at first seem to be a good idea. However, if this lineup is on a Dynasty mode and you want to keep them after year one, you will be in deep trouble. An expensive tag on an old or poor player may mean that they are retiring soon or have long contracts.
Bigger, stronger players can deliver a more powerful shot with a stiffer flex. Smaller players however do not have the strength to utilize the stiffer flex settings. When creating or editing a player, make sure to consider his strength when choosing the Stick Flex setting.