Maybe I missed it, but what kind of lights are you using? If they are low wattage (20-40w) CFL's, they should be 1-3 inches from the plant, or as close as you can get them without burning the leaves. A fan blowing on the plant will help this also.

What size container is that (how much soil)? And what kind of soil (brand, is it pre-fertilized)?

As for giving nutrients, this depends on your soil. If you are using Miracle Grow, you won't need nutrients for about a month. As long as they are green and look healthy, they don't need nutrients. From the pics it looks like you'll need a larger container pretty soon, and when you do re-pot (with MG for example), you can go another 3-4 weeks without nutrients.

Not really sure which pot size is best at this point, but check out some other grow logs and see what other people have successfully used.

Once those nutrients run out, however, your best option is to get nutrients made specifically for growing cannabis in soil (Fox Farm, Canna). You can get away with other types, but the results are usually not as good. If you go with MG nutrients, find out the NPK numbers on cannabis specific flowering nutrients, and try to match them (more N for veg; Less N and more P and K for flowering- which is what you want since you are flowering).

I don't think changing the light schedule matters at this point. It's an autoflower, it will produce flowers under any light schedule, but I don't know which schedule is the best. I'm sure there is some information out there about the best schedule, but until you find it, just leave things as they are.