I always have trouble sticking with my workout routines and diets. For workouts I use the nike+ training club app. They organise workouts by how much you exercise in a week, separating that into beginner, intermediate and advanced. They even have 4 week workout plans that are designed to do what you want, get you toned, get you skinnier, or get you stronger. Once you reach certain minutes worked out, the app will give you little trophies and things. However, even the beginner workouts can be very intense.
The way the 4 week plans are set up is two days on, one day off. So workout Monday and Tuesday, rest on Wednesday, then back on for Thursday and Friday.
I don't have the money to join a gym, and my university has one on campus, so if I ever decide to go I can use the one on campus. However that's always full of our sports teams and I feel sad when I'm just walking on the treadmill and they're all running at really high speeds.
For diet, I like to use the myfitnesspal app. It shows how much of each nutrient I've eaten, and since my workouts are in Apple's Health kit, it can pull them from that and add extra calories to my daily limit based on how many I've burned that day. So if I burn 150 calories, I get an extra 150 calories on my daily limit.