Tips for Golfing in Batch
Counters

Whenever you have a variable that will act as a counter starting from 0 you might want to write

set count=0
set/acount+=1


; however, you can eliminate the first lines because whenever set/a is used with an unset variable its value is assumed to be 0  

set/acounter+=1


Code Blocks

There a number of ways you can shave off a few bytes when you have to used blocks of code.

Whenever you open a code block, you do not need to insert a line break before the first line of code in that block. The closing parentheses does not have to be on a line of its own either.

If %a%==%b% (
     echo true
) else (
    echo false
)


can be golfed to

If %a%==%b% (echo true)else (echo false)


Printing Without Trailing New Line

The common pattern for this is 

echo|set/p=text


but, you can save 2 bytes changing echo to cd

cd|set/p=text