Friends, I am not a an expert in explore strategy but I would like to share my experiences with explore.

1. Upload only quality photos
2. You have to enable exiff and geo-tag your photo
3. Every day explore algorithm changes but I think its always checking number of views, comments and faves.
4. Rate/ratio of views, comments and faves is very important. Like for example if a photo has only 10 views with 8 comments and 7 faves it is rated higher than a photos with 100 views 50 comments and 10 faves. Similarly a photo with 10 views 8 comments and 7 faves in one hrs is rated higher than a photo with 10 views 8 comments and 7 faves in two hrs.
5. Posting to groups is very important. flickr want to promote meaningful groups. So a if photo has got 5 comments from friends and 6 comments with group signature is rated higher than a photo with only 11 comments from friends.
6. Another important thing is to which group you are posting to. Each day is special and for each day flicker identifies and promotes some particular group. We have to identify those groups post our photo and get comments from it.
7. If you post a photo to a group and you never got any comments with group signature you will be rated lover.
8. Now the theme, each day is special and a theme is associated with it. Example HBW.
9. Now most important thing .. the x words. Flickr has a long list of x words or banned words. Ie if any of the ‘x’ words happened to get in to any comment or tag or tittle you are screwed. Now only thing you can do is remove those comment or tag or re write the tittle, else you will be dropped out of explore in minutes.
10. Explore ranking depends on your friends popularity also. If you get a comment from most popular guy in flickr. You are gonna get a better explore rank.
11. When you comment on some pictures of your friends/contacts, if you get a comment as a reply your rank goes higher.
12. last but not the least : what is it?? I dont know .. its unknown. Identify it.