The elongated stems means you need more light. If you use supplemental lighting the plants should be kept just below the light source.

The toppling and dying could be from damping off, a fungal disease. Try sterilizing your soil by pasteurizing in the oven or use a soilless starting mix. And water from the bottom.

Here's a look at one of my starts. I use a 3 tube LED grow light for 12 hours a day. I also brush the top of the plants with my hand twice a day. You could use a fan, but I like the personal touch.