I never use "likewise" without incorporating it into a repsonse to a compliment or well wishes that a person gives me. Its just not a word that gets used very often outside of those circumstances. For instance, somebody might say, "Have a nice day," and a common response would be "Likewise," i.e., "I hope you have a nice day, too." You wouldn't respond with "similarly" in that situation; it wouldnt make any sense. Outside of that situation, I would just avoid using the word "likewise." It's a bit confusing, to be honest.