Hydration is KING. Drink as close to 64floz of water a day as you can. Next is being active, doing something physical that makes you sweat for at least 30 mins a day is ideal (no, jacking off doesn't count). Finally, tailor your diet and lifestyle. Stop smoking and drinking habitually, eat plenty of veg and fruit, and make sure you consume enough zinc through diet. Not supplements.
Whatever you do, don't fall into supplement traps. They are expensive and provide negligible returns for the probable side-effects you'll have.
I seriously cannot stress enough the hydration part.
What are your thoughts on the "cum holy grail" supplement stack? Whenever I can manage to keep up the regimen for enough time, I've noticed significant results, but I'm skeptical that it's a placebo effect.
Before I film a facial or a deep creampie, I do a diet of drinking a glass of beet juice or pomegranate juice before eating anything , and eating fruits and vegetables right after like, celery, lots of spinach, banana, strawberries, carrots… etc
Drink lots of water, edge for an extended period of time, and make sure its been a couple of days since you last ejaculated. You want to feel like you're ready to erupt just before you cum.
Another thing that is important: stress and low mood can really affect sexual performance in every way. Being in the mood and feeling good will almost always make you cum harder.