</font><font color="blue" class="small">( Hi Bob. I have a one row unit. Still working on the math to make it work out! Also, trying to figure out how to keep straight with these rows! )</font>
PRACTICE....PRACTICE....PRACTICE.....
Don't look at your front wheels. (or at least don't STARE at the front wheels.) Just look at them every now and then, checking to see if you're still "on track" with the previous row. Look far out in front of the tractor. When you stay focused on the front wheels, you will have the tendency to make constant "corrections". Looking out at a distance, focusing on the end of the field will make those adjustments less frequent, and more gradual.
A single row planter will be difficult to use with a tractor that's not "single row width". Multiples of 2 rows (2, 4, 6, ect...) work best. HOWEVER....
It isn't the end of the world, running over a planted row. It is FAR better if you don't.
For many a year, corn was planted in 40" rows. The main reason the switch to "narrow row corn" was made was to increase "plant per acre" population. By planting in 30" rows, as opposed to 40", seed can be dropped farther apart in the row, and still get more seeds per acre. That helped with planter accuracy as well. (It also allowed planting at a faster ground speed.... something that most farmers felt neccisary.... Even with todays more modern, highly improved planters, it isn't recommended that you plant faster than 5MPH. )