I'm growing three varieties of tomatoes from seeds I saved from last year's harvest: Black Cherry Tomatoes, Cherokee Purple Tomatoes (my favorite!), and Hillbilly Tomatoes.
I like to make origami pots for growing seedlings because then you can place the whole plant/pot right into the ground (or into a larger plastic pot) without disturbing the roots. You can learn how to make your own origami pots at this blog post written a while back: Origami Pot Tutorial.
Once the origami pots are made, fill them with soil, put a few seeds into each pot, place them in a tray, and water by filling the tray not the individual pots. (The tray I'm using this year is a recycled pastry box because it was the perfect size for just a few pots.)
Place the tray with the origami pots over a warm place like the refrigerator, the boiler, or a heat register. This gets the seeds warmed up and growing quickly. Beware not to leave them over this warm place for too long because the seedlings will shoot up too quickly and die. I place my tray over the boiler in the basement.
Once the seeds begin to sprout, I move the seedling tray to a work table (also in the boiler room) and hang a shop light over the seedlings. It's important to get the light close to the seedlings so that they don't have to "reach" up to the light. The close lighting helps them grow slow and strong. There are growing lights specifically made for growing seedlings but I have always used a shop light plugged into a timer and it works just fine.
It's been 5 days since I started the heirloom tomato seeds and nothing has sprouted. I'll give it a few more days and if still nothing, then either I'll buy some seed packets or just get some starter plants in May.