hi,
try creating your own tactic. Of course there are some great tactics you can download from here but none will be perfect for you as each team has different players and the tactics have to be build exactly on that. Try to get from scrap and start with a 4-2-3-1 formation with 2 CMs and not DM. Put your wingers who probably will be grosskreutz and reus as IF and levandowski as a poacher or an complete forward. Think how would your team play better: slow and short passing or fast with directs? I would suggest the second one as you have some full speed players that can hit and score on counter attacks.
Dortmund is a fun team to play as you have an offensive team with great young players so you probably won't need any transfers at all so your squad harmony should be very good from the beginning. Also, try to get most from goetze. Play him as an AMC with lots of creativity and through balls. let him move more and it will pay off.
Even if the tactic you will create won't be perfect from the start, try to fix. watch the games and decide what you like and what you don't and act accordingly. The thing with FM 13 is that no tactic suits best your team unless you adapt it so you will be surprised if you will get a tactic from other guys and it won't work for you even if it won leagues for others. You will have to adapt it and in the end you will invest the same amount of work as you would have build it yourself. Just do it from the start and don't waste your time.
At least this is how I do it.
Good luck with Dortmund and bring the 3'rd consecutive title home.
