Ridged Spider Web is a wonderfully useful stitch to create spider webs, hubcaps and lots of other round items. The folks at Needlepoint for Fun have a great tutorial showing you how to do it. Learn here: http://www.needlepoint-for-fun.com/handy-needlepoint-stitch-for-spokes-rays-and-spider-webs.htm
Try this tip from Jo Ippolito Christensen for securing thread ends. It works great for ribbons, pearl cotton balls and other threads. Use Scotch Reuseable Strips. Cut off a bit and place on the end of the thread. Press down to secure.