Which transfer paper was it? There will always be a "window" around your design unless you use a cutter to contour cut out the printed area and get rid of the unprinted area. A lot of people only bother doing this with transfers for dark shirts (since the transfer will be a white rectangle otherwise) but you can do it with light transfers too to completely get rid of the "window". Some are worse than others, however, JPSS is generally the most highly rated one for durability and "feel".