Looking to improve your abdominal muscle with gym workout then this is best exercises. Must perform all the exercise with proper posture and controlled movements and try to lift as much heavy possible. You must learn about proper warm up and cool down after workout. click on names to find How to Warm-up before workout? and How to Cool-down after workout?.
You must also learn about Static Stretching for avoid DOMS. Delayed-onset muscle soreness (DOMS) is muscle pain that begins after you’ve worked out. It is also advisable to start with light-weight a few 2-3 sets of your first exercise and consider it as your part of the warm-up.
Instead of body-weights exercise you also can choose a treadmill or cross-trainer as your warm-up for 10-15 minutes before workout.