Daredevil, Jessica Jones and Agent Carter I will make the conscious effort to watch every episode, they're pretty much the perfect example of comic book shows done right and are amazing.
The rest I follow but don't ensure I watch every episode. Agents of S.H.I.E.L.D. is remarkably good given all the hoops it has to go through and the fact that it is always altered by the films yet can never influence them, has about a tenth the budget and none of the main film characters will ever appear in it.
Arrow was really good for seasons 1 and 2, something happened during season 3 where it got crap, it has gotten a bit better for season 4 but the villain is so ****ing dull and non-threatening. The Flash is pretty good although the flash saying he's the fastest man alive when every single speedster villain he faces is much faster than him is funny in the wrong way. Legends I watched the one in the future of Star City and wanted to like it for Sara Lance and Rip Hunter as I like the actors but Vandal Savage isn't scary when he's died about 5 times in the show already, feels like its trying to do the Firefly formula but didn't get the mix right.
Gotham got a lot better in season 2 although I do think they're introducing a lot of the Batman villains at once, the Jerome character was utterly fantastic (I actually really hated that they put him in at first but the performance won me over).