Good light matters more than anything else.

Three things: light, warmth, and moisture. That’s it.

Get a seed-starting mix (not garden soil), fill some clean containers with drainage holes, plant seeds at the depth the packet says, and water from the bottom so you don’t disturb them. Cover the tray with a clear dome or plastic wrap until they sprout.

Heat is helpful for germination—a heat mat speeds things up, but a warm room works fine for most crops. Once they pop up, the dome comes off and they need bright light immediately. A south-facing windowsill is rarely enough; seedlings get leggy fast. A cheap LED shop light two inches above the tops works better than a fancy grow light mounted too high.

Keep the soil moist but not soggy, give them 14–16 hours of light per day, and transplant after they have two sets of true leaves and the weather cooperates. Don’t overcomplicate it.

You’ll kill some. That’s fine. Next round will be better.