I think you did right your first year for your HC. Ambition is important the first year, because it makes all the special skills cheaper. You have to get Charm and Charisma the first year, because it affects approval and can keep you from getting fired the first year. I always start out getting Offseason regular Seminar, Regular season seminar, and Playbook training to help learn the playbook. It only lets me get to Performance 2 before I start my career, but I get it up to 3 during preseason. Leadership, if you have enough to get it the first year, will make all your subordinate coaches better at player development.
Concentrate on player development for your assistant coaches, and learn special skills for your OC, DC, and Head Coach. As for Performance, level 3 is good enough for the first year. You can max it out later in your career. I'd concentrate on player development for the HC AFTER I've gotten all the specials skills that are important starting out. Of course, it's only my opinion.