Try these methods for beginning a thread, then decide which one is best for you.
Securing the thread
1: Securing the thread: Start by pulling needle through fabric back to front, leaving about 1" behind fabric. Hold this end with fingers as you begin stitching, and work over end with your first few stitches. After work is in progress, weave end through the back of a few stitches.
2: Waste knot: Make a knot in end of floss and pull needle through fabric front to back several squares over from where your first cross-stitch will be. Come up at first stitch and stitch first few stitches over floss end. Clip knot.
3: Loop stitch: This method can only be used for even numbers of strands. Cut strands twice the normal length, then take half the number of strands needed
and fold in half. Insert loose ends in needle and bring needle up from back at first stitch, leaving loop underneath. Take needle down through fabric and through loop; pull to secure.For even stitches, keep a consistent tension on your thread, and pull thread and needle completely through fabric with each stab of the needle. Make all the top crosses on your cross-stitches face the same direction. To finish a thread, run the needle under the back side of several stitches and clip. Threads carried across the back of unworked areas may show through to the front, so do not carry threads.