It's not only about the start date and trip cost. In photo blog, the originality and quality of the pictures is most important. If you didn't get any point then your pictures are not upto the mark. I also did a photo blog without any start date and trip cost but still I managed to earn some points.
Hi Yoshita, in order to earn credits your posts must be approved by Tripoto's system and there are certain parameters on which your posts are checked. You can go through them here: https://www.tripoto.com/tripoto-credits
Actually photoblog is about a photo and a good caption and trips is all detailed information. so in photo blog there is limit trying to post trips instead of photo blogs