Most people would say retire and start over this offseason. I would have to agree that might be a good idea but wait till the offseason to retire and create another player.
Then a simple tip to get you going in the right direction is to pick your first skill and spend all SP you get till it reaches a minimum of 73 without equipment. You can train your next skill while you are building your first skill.
Most linemen start out taking strength to 73 or higher before addressing any other attributes.