In over 55 years of gardening, I have several tricks for growing from seed.
I start most seeds like broccoli, tomatoes, etc in a moist bounty towel , spaced evenly, in a zip lock bag. I usually get 99% germination.
I hold it up to the light after 5 days, checking to look for small roots, then tear around the root if it is attached to the bounty, and plant the root or root and bounty, into a starter planter, one at a time, and drip wet them in, transplanting after 2-3 leaves later into the garden.
Once I have used the seeds from any year, I put the remainder in a Zip lock bag and into the freezer!
I just did a "Germination Check" in the bounty/zip of ten year old Bush bean seeds, and 100% Germination!
That is a good way to check viability of almost all seeds!
As for lettuce, not worth that effort, so I direct plant in the garden.
Here is how I successfully do it from seed. I loosely rake the soil, thinly scatter the fine seeds on top, walk on the row or block to press the seeds onto the soil. I then take an old white sheet, place it over the seed bed, and wet it thoroughly! I keep it moist, never letting it dry more than a day, and lift it after 5 days to see if they are up. If not, I check every 2 days!
The advantage I have found is that the sheets keep birds, bugs, etc from feasting on the seeds, as well as any heavy rain from washing them away. I do the same method for carrots, beets, Asian greens, and Savoy cabbage.
A GREAT alternative to lettuce is Komatsuna, (Japanese Spinach Mustard). It grows fast, and starts supplying a steady supply in 4 weeks! I eat a lettuce salad most nights. Now I mix 60% komatsuna to 40% lettuce, and I cannot tell the difference!