Please read!!!! New attempt for a big plant

Im looking to grow 1 plant for a maybe long period of time to try and get a high yeild

Atm all i have is a 20L pot no lights or nothing as i got rid to get new set up.

To cut a long story short what do you guys think i should attempt to get big YEILDS!!! and a nice smoking tasty bud

.STRAIN
.Lights
.should i train it
.what feed
.ECT

Area of Grow 3 by 3 foot and hight is bout 8-9 foot (i no not huge) but good enough for 1........ ANY HELP WOULD BE VERY HELPFULL TO MAKE A FAIRLY NEW GROWER HAPPY ON THE ROAD TO GREAT THINGS THANKS!!!!!!!!!!

Plus i must add any tips on veg stage too !!! Thanks again

I'd say a 20l pot is a bit much for that kind of space. You don't want to veg it for too long, I'd say 4 - 6 weeks.
Lights will depend on your budget, get yourself a 400W HPS if you can, or since you're only gonna grow 1 plant you could go for CFLs if you don't mind the smaller yield.