1. Lots of short fun sessions... daily. You can't make up for missing 2 weeks of 10-15 minute sessions by going 2 hours.
2. Start with the basics... name, come, sit/stay. You need to have control of the dog before you do more advanced stuff.
3. 90+ % is positive reenforcement (voice/tone, praise, snacks). The negative reenforcement needs to be very measured. Again your voice/tone are key. Body language, general dominance is often all that is required. A firm grab by the scruff can be just as effective as a smack. Not saying never smack em just make sure as you get firmer and firmer that the dog really knows why he's being corrected.
4. If you get frustrated, end the session. But try to do something easy so the dog can end on a good (+) note.