You don't want to indicate the video is finished, so I have tried to teach myself to point out that another video is related to this one and needs to be watched now "click this thumbnail on screen to be taken to ------------ (insert reason why it's important to be watched)"
I generally try to have a video that's related to the one just finished in the end card to make it easier to pass traffic on in the video it'self. I also try putting playlists sometimes when it's related.
You definitely want to be recording your video, or voice over WITH the end card in mind and with the next video in mind, so you know for those 10 seconds where people will be going next so you're not ending the video and getting right to the next point of action.