my daughter is 10 month.she has not started to crawl..what should i do...

What i did to motivate and guide my son is, i always let him lay on tummy, and i will put a toy in front of him, and i help him by putting his 1 hand forward than the other hand forward and push his 1 leg up follow by the other leg. P.S. : my girl is slow, hence i scare he will be slow, and did a trial, and he is picking it up slowly when i teach him.