Crazy as it sounds, I love Miracle Grow's Seed Starting Mix. Fox Farm Light Warrior is pretty good as well. Although I've done great in coconut coir too. The most important thing is that it's light and sterilized. If your directly sowing in the garden, avoid adding uncomposted manures until the plant is mature. The heat from the composting can kill seedlings.
I don't use heat mats or do anything to pre-germinate them. I start my seeds in one gallon smart pots, indoors under a 200W CFL. I keep the lights running 24hrs on until they pop, then I switch to 18hrs on and 6hrs off. The heat from the light is enough to germinate them, even when room is 70*F to 76*F. Plus as soon as they pop they immediately get light, so they don't come out looking stretched and break from their own weight.
Lastly, I also wet the seed starting mix before I fill the container. Then I sow 1/2" deep and lightly mist. I'll continue to mist as needed to keep the top inch of soil lightly moist, but not saturated to the point where if I was to grab the container and squeeze it, water would come out. It just has to barely be moist. Mine all usually pop within 2-3 days. Here's a photo of my setup: