We tried everything with Caden to get him to like tummy time to no avail. He finally got it at around 6 months when he could roll well back and forward, then crawled at 8 months and walked at 10 months, so I really think that he just developed in his own time. My sis has just had her 4th bub and is amazed at how much has changed since her second youngest who is five. She says tummy time was not such a big issue then, and her bub crawled at four months, so although it is important, if they don't like it then it is not the be all and end all.

Good luck!

PS there are "tummy time nazis" out there that harp on about how important it is. But I believe a happy bub is more important, so ignore them if you can