http://www.glb2scout.com/This is kind of a must imo.
It shows what plays work against what and what plays don't work well at all. If your opponent uses it and you do not you are already at a huge disadvantage, especially if you are not already experienced and established.
Low chemistry will greatly hurt your performance. You have a lot of extra cap room so you can afford high contracts which will help chemistry recover faster. I would start with your HB and CBs for sure.
Try to sign players mostly in the offseason where they can start at 50 chemistry. After I believe week 5 any human player you sign will be worthless starting at 0 chemistry. It is best to stick with CPUs after that point. This is a mistake I see so many teams making. The one exception is if you can secure a super star or hard to recruit position for future seasons.
Don't be afraid to reset a few times to get organized and correct mistakes you made before. Rookie is a bit more forgiving that other levels. You will have a chance to play other inexperienced teams. The higher you move up in tiers most of those teams will be gone leaving only experienced teams in the tier.
Sponge the forums, get the scout tool, and ask lots of questions.