While To Love-Ru starts off as a nice lightly ecchi rom-com, the longer you stick with the series, the lewder it gets. It is nice to ease into things because ecchi is often more fun when you are more familiar with the characters, to be perfectly honest.
If you are looking to continue To Love-Ru after the anime with the manga, you should know that the original To Love-Ru anime – as in the To Love-Ru anime, OVA, and Motto To Love-Ru – fully adapted the story from the manga. That said, the anime adapted the manga pretty poorly. Tons of content from its 162 chapters was skipped in the anime, so there is definitely some merit in going back and reading the series from the beginning despite there not really being a set point to pick it up at in the middle.
To Love-Ru Darkness, on the other hand, is a different story. To Love-Ru Darkness was originally set to be a spin-off of the original before it became a full on sequel to it. If you have finished the ecchi wonderland that was the To Love-Ru Darkness anime (including both seasons and the OVAs), you can pick up the manga at Chapter 55 in order to continue the story. It does skip Chapter 51 – 53, though. So you may wish to read those.
If you did not watch the OVA for To Love-Ru Darkness the 2nd, then you will want to start at Chapter 49.
