Remember, cross-stitch is considered counted embroidery.
So count count count count again and double check your counting. It really helps minimize mistakes.
Gridding save you a lot of time (and your sanity too). Cross stitch is meant to be relaxing. Make your hobby hugely beneficial for your mental and physical health.
Material Type: Aida Generic White
Sewing Count: 14/inch or 55/100mm
Design Size: 90 x 90 stitches
Sewn Design Size: 6.4 x 6.4 inches or 163 x 163 mm
Suggested Material Size: 12.3 x 12.3 inches or 313 x 313 mm
Stitch Style: Cross-stitch Using 2 strands