Paper piecing takes condidence, so don't give up.
Here is another little trick. After you havd sewn that little seam and are going to fold back your paper to trim with the 1/4 inch ruler, hold a stiff postcard like you get in the mail sometimes along the sewing line. Your paper will fold back so easily and straight. Then put your ruler along the paper and trim.
Also, if there are many seams with really small pieces, there is a 1/8 inch ruler, too. This one makes those seams smaller and there is less bulk.
I am not fast a paperpiecing, but sometimes I just like the pattern and want to do it.
Have fun!
Anne in AZ