A dark, rich mehendi stain isn't just about the paste quality - what you do before, during, and after application all affect how deep the final color turns out. Before application, exfoliate the skin gently and avoid using any oil, lotion, or moisturizer on the area for at least a day - henna stains dry, clean skin far better than skin with a barrier of product on it. Warm skin also takes color better than cold skin, so many artists recommend a warm shower right before the appointment (just make sure skin is fully dry before the paste goes on). During the sitting, keep the paste on as long as you can reasonably manage - a minimum of 4-6 hours, ideally overnight for bridal mehendi. This is the single biggest lever you have. No aftercare trick makes up for removing the paste too early. Once you scrape off the dried paste (never wash it off with water, which removes unset dye), apply a mix of lemon juice and sugar, dabbed on lightly with cotton, every hour or so for the first few hours. The sugar makes the mixture sticky so it stays on the design, and the acidity helps the stain darken as it oxidizes. Avoid water contact for at least 12 hours after removing the paste - no handwashing with soap, no dishes, no bathing that gets the area wet. Water this early actually lightens the developing stain rather than helping it. After the first 24 hours, keep the area moisturized with a natural balm (mustard oil, coconut oil, or a plain balm without added chemicals works well) - this helps the stain stay dark for longer rather than fading in patches, since dry skin flakes off and takes color with it faster than moisturized skin. Finally, avoid chlorinated pools, harsh soaps, and excessive hand sanitizer use in the first week - all three noticeably fade a mehendi stain faster than normal daily activity would.