Top 5 most viewed episodes of H!S (at the time of this post)1. #26 (926.614 views)
Wagamama Ki no Mama Ai no Joke (MV), Hello! Project 2013 SUMMER COOL HELLO! ~Sorezore!~, Ai no Gundan (MV)
MC: Suzuki Kanon
2. #25 (658.816 views)
Ai no Gundan (Dance Shot Ver.), Massara Blue Jeans (LIVE), Yattaruchan Strategy "throw the first ball", Kokuhaku no Funsui Hiroba (Tsugunaga Momoko), Uemura Akari Interview
MC: Suzuki Kanon
3. #52 (549.237 views)
Otona na no yo! (MV), Kimi no Kawari wa Iyashinai (Dance shot), Morimusu, Samui ne. (LIVE), Ishida Ayumi hair arrangement, Morning Musume video
MC: Ishida Ayumi
4. #50 (495.381 views)
Kimi no Kawari wa Iyashinai (MV), Hello! Project COUNTDOWN performances, Yajima Maimi and Wada Ayaka hair arrangement
MC: Sugaya Risako
5. #47 (433.573 views)
Egao no Kimi wa Taiyou sa (MV), LIVE Perfomances (Oheso no Kuni Kara Konnichiwa, A B C D E-cha E-cha Shitai, Tokai no Hitorigurashi), Hello! Station dance unit practice
MC: Kudo Haruka
So the trick for an episode with a high viewcount seems to be (so far): put a Morning Musume MV (any version) on it. Two works even better.
Either that or it's the live performances, but I'm leaning toward the former.
http://helloproject.wikia.com/wiki/Hell ... ct_Stationhttps://www.youtube.com/user/helloproje ... &flow=list