When my son was 8 months old i was worried like mad because he did not crawl too. Then one day he suddenly started dragging himself to move forward by stretching his hand and pulling the bed sheet.
Was happy cause thought he will be crawling. Waited and waited, kept trying to help him by putting my hands on his sole, used all kinds of toys to try and get him to crawl over. Just when i thought he will never crawl (worried cause heard babies who do not crawl will have coordination problem), he suddenly started crawling at 9 months.
Then he started pulling to stand at 10 months and cruising at 11 months. Thought he will walk at 12 months but he did not. Now, at 13 months, finally he is walking few steps (about 10 steps) independently.
All babies will develop at their own pace so dont't worry too much.