You could run what is called a water table board at the bottom.
Basically it starts out level and you cut the bottom to fit the area it falls down to. That make sense?
You could use the new vinyl trim boards available, or even a couple pressure treated boards painted.
Another option is to buy some coil stock and cover the showing siding below your starting point that way.
Some others may have some more ideas, but crooked always shows up in my opinion.