So you have the report in hand, holidays are sorted and you are ready for Term 3. For some, if things keep going the way they did in the first half of the year then Term 4 Report might as well be a carbon copy of the first. To make a structural change can be one of the hardest decisions one can make. For the time-poor High School student working 3 nights at Maccas'' plus Oz Tag plus weekend sport, a party here and there, Facebook, Snapchat, Foxtel, food, fun, families, friends, fitness, Gaming .... then comes homework, study and sleep.  For the average teenager the appropriate balance can all get a little too much so time for parents to step in and prune what needs to be pruned! 
A myriad of choices exist here and you need to choose the right option to get the best out of your child and preserve family life. Including your teenager as part of the decision is a wise choice. The main thing is to have the conversation that needs to be had. Make the decisions that need to be made, and evaluate those choices on the run. Hopefully those structural chances are a windfall and benefits are noted in improved grades and a happier, more energised teenager, who may even have more time for you! Good luck with that :-)