Having an intense workout can effect on what fuel the body uses and what kind of adaptations the body makes after exercise. There are a variety of ways to make your workouts more intense resulting in optimum results. 

When working out with weights, always aim to train to failure (complete repetitions until you can no longer complete good form during the concentric (lifting) part of the movement). You can include a variety of training methods to make sure you hit a variety of rep ranges while involving both types of muscle fibers. Methods you could include:

• Multiple Set- this is performing a multiple number of sets for each exercise e.g. 3×10
• Ascending Pyramid- this is increasing the weight while decreasing the reps each set, e.g. 60kgx12, 70kgx10, 80kgx8.
• Descending Pyramid- this is starting off with your heaviest weight then gradually decreasing the weight while increasing the reps. An example of this would look like; 80kgx8, 70kgx10, 60kgx12.
• Superset- this is performing two exercises back-to-back while taking minimum rest between the two. There is two main ways of doing this- using the same muscle groups (agonist), e.g. supersetting bench press straight into bench flys. The other way would include supersetting opposing muscle groups (antagonist), this would look like suppersetting bench press and bent over row. 
• Drop set- this is would involve performing a set to failure, then removing a small percentage of the load and continuing with the set. 
• Tempo-Aim for a 2-3 second eccentric on each rep and then be the most explosive on the press. If you don’t go slow on the eccentric, then your are going to be mainly training your joints rather than your muscle. 
• Pivotal Rep Set- This is when you will perform 10-12 reps aiming to hit failure, rest 20 seconds then aim to fail between 6-8 reps with the same weight, then to finish; take a 5 second rest then hold the weight up for as long as you can (isometric contraction), aiming to fight against the resistance until reaching failure 
• Rest Pause Set-  this is where you will perform 3 sets in 1, with a 20 second rest between each. An example of this would be; perform 8-12 reps until failure, rest 20 seconds, complete 6-8 reps until failure, rest 20 seconds then complete 4-6 reps to failure (all using the same weight). Another example of this would be performing 8 sets in 1; starting with performing 15-20 reps, rest 45 seconds, train to failure, rest 30 seconds, train to failure, rest 15 seconds, train to failure, rest 5 seconds, train to failure, rest 15 seconds, train to failure, rest 30 seconds, train to failure, rest 45 seconds and then finish off with one more failure set. 
• Forced reps- this is when you hit muscle failure and require a partner to assist in completing past the normal point of failure.  
• German Volume Training- this involves 10 sets of 10 reps at 60% of your 1RepMax with minimal rest (60 seconds). If you are using this method- mainly focus it on one exercise per workout e.g. if you were training legs then perform this rep scheme while squatting. 
• Occlusion Training (Blood Flow Restriction Training)- this is a technique that allows you to perform at a lower intensity exercise(20-30% of 1RM) with blood flow occlusion that produces similar results to high intensity training, This involves the application of a cuff to the muscle that is being trained and have minimal rest time intervals between sets (30 seconds)
• Resistance bands- movements will have a strength curve, for example; in a hack squat your lowest point of strength is going to be at the bottom of the movement- this is also were all the stress is placed on your joints and ligaments. Using a band can help you have all the weight at the top of the movement where you are stronger and then once you start to lower (eccentric), the bands will start to kick in which will help you at the weakest point. This will allow you to add extra weight while taking the impact of your ligaments and joints in the weakest part of the curve.