You should have a plan in place to reach your goal, a realistic goal - maybe 1-2lb a week or 4lb per month or inch loss - it should be something that can be achieved. Rather than saying I need to lose 3 stone and that's that! First, break it down to what can do you daily/weekly/monthly to achieve that.
Here are some things I recommend you do when trying to lose weight. 3-5 training sessions per week lasting around 30-60mins depending on intensity and fitness level, this time could be more again depending on you and where you are at. On rest, let your body recover. The most exercise I will do on these days is walking the dogs and getting my steps up (>10000).
Keep track of your workouts and your weights, reps etc bring a book with you and record each workout for example week 1 squats you had 30kg on the bar then week 2 add maybe 2.5kg more to the the bar this way your you can see your progress or keep the weight and add more reps.
The other thing to track is your food I use my fitness Pal and what I do is track ahead for the next day like today I will put in some of the food I will be eating this way I can see what I can allow for a treat.. chocolate really
this is not restrictive or obsessive it's basically a life saver it's the only thing that's worked for me, and it's a REAL LIFE DIET! Remember you cannot out train a bad diet, your nutrition will be priorty... The car won't run without fuel!