The two top ones can serve as a 'so do I' or 'me too' in every situation I can think of. Just make sure they're not your sole contribution to the conversation.
For the bottom two you can also change the verb to mimic that of the sentence you're agreeing with, even if it's not strictly necessary to do so:
Ja, det synes jeg også.
Yes, I think so as well.
Using these longer and "customised" versions will make you seem more engaged in the conversation, even if all you're doing is parroting back your conversation partner's sentiments. It's also a good way to learn the language!