An optimal warm-up to increase the weight that you lift during your working set(s) would be as follows:
Let’s use the barbell bench press as an example with a goal working set weight of 225 lbs.
5 minute warm-up on the cardio equipment of your choice.
Dynamic warm-up exercises to warm-up the shoulders, chest and triceps.
1st set-5 reps-45 lbs.
2nd set-3 reps-95 lbs.
3rd set-1 rep-135 lbs.
4th set-1 rep-185 lbs.
Working set (4-6 or 6-8) reps with 225lbs.
I guarantee that the weight that you normally use on your working set will be increased by 5-10% with this method.
Please let me know how this warm-up works for you.