Mistake 1:Thinking more is better.

Many people actually work out too much. By completing workout after workout without allowing for recovery, your body never gets a chance to recover and therefore tone or build muscle effectively. By over training you will start to see you workouts suffer. As the weeks progress you will start to feel fatigued much sooner during your workouts. After as little as three consistent weeks without a break, burn out, staleness, and symptoms of overtraining will appear, leading to potential injuries and a regression in your results.

Instead, work out three to five days a week (performing two to three strength workouts and one to two cardio workouts). Give yourself at least one complete rest day, and switch up your workout between “hard” and “easy” days. That will help your body recover so you get the most from every workout. Remember your body will only grow and tone while you rest so don't over do it!

Mistake 2: comfort zine training

Performing lots of repetitions with light weights and plodding along with easy cardio without breaking a sweat! The problem is that your body will only get fitter, tone or build if you force it to, taking it out of its comfort zone. Your body is a master of survival and it will always do the least amount possible holding back fat for reserves. When it gets used to a routine, it becomes more efficient, so it uses less energy. Si basically You burn fewer calories and build less muscle.
You don't have to kill yourself to get results but tonight just take it up a notch and push harder, lift heavier, sprint at a max effort, and dig deep to really push your potential. Don’t be afraid to sweat you might actually like it!

Mistake 3: doing the same routine over and over

Ad iv just said your body will do the least possible because it liked to keep some fat stored up. Your body is constantly adapting to whatever demands you put on it and in only 3-4 weeks it's learnt how to conserve energy from your workout. So change things up! Strength training is reliant on the nervous system being challenged to adapt.
It's easy to change up your routine.
If you have been running a lot, completely stop running and start lifting weights. If you have been taking spinning, stop spinning and get to your local pack for power walk and runs. Whatever you are doing after 3-4 weeks stop and do something your body isn’t used to. It is good to take a break from an activity so you can come back to it later as a new, challenging demand.

Mistake 4: thinking lifting heavier weights is the only way to tone up

Basically it's not. Your strength and muscle-skeletal system is totally reliant on your nervous system so stimulating and challenging that will cause muscle improvements. Yes one way of doing that is lifting heavier weights or doing now reps but it's not the only way and in many causes not the best. Try changing some of your toning exercise to unstable environments using stability balls, bosu, or Dina discs to cause your nervous system to "fire" more muscle fibres. If you exercise in unstable environments you have to use more muscle to stop you falling over- this means more calories burnt, faster toning and greater adaptations in muscle size. Whatever your goal, training this way will help and is a great way to mix up your training.

Try this:
Ball chest fly
Ball French press
Single leg shoulder press
Ball Jack knife