To write hooks, you have to listen to music that is hook oriented. If you listened to death metal all day long for a month, your hook writing skills would not be any better. If you listened to super out of the box jazz, your hooks would not come. If you want hooks, you have to live hooks and understand how they are created.
As a guitarist, it was very easy for me to practice, learn scales and shred with my 80's heros. However, "phrasing" was something that was NOT in my style at all at first. Guitar was more of a scale sport to me. I'm glad to have grown out of that, but the stuff I learned in that time is priceless to me now. You see, phrasing is a totally different animal and ISN'T so easy because it is NOT a boxed scale pattern that you just learn. You can't teach phrasing anymore than you can teach someone how to write a memorable hook or how to be melodic.
Melody, hooks, they are all feelings. But rest assured, if you surround yourself by bands that are famous for infectious hooks, they will rub off on you eventually and you will find yourself singing melodies that belong to you. It's ok to be inspired by a song and use its formula while playing a few parts backwards. This is how we grow. Leaning how to come up with hooks is like studying anything else really. The more you search and learn about them by listening to, playing along to or even covering a famous song, the more you get in the "infectious hook" frame of mind. But you really have to go deep into it. Whether it be popular country or the pop/dance/R&B/soul genres or heck, even little kids music....the hook is where you need to concentrate. Grab any Disney movie and listen to the music. The hooks are brilliant even when the soundtrack is NOT sung or performed by anyone famous.
Justin Bieber..brilliant with hooks even though quite a few he hasn't written himself.
Britny Spears....great hooks.
Janet Jackson....awesome stuff..
Celine Dion, Mariah Carey, Whitney Houston, Michael Bolton, Richard Marx, Journey, Bon Jovi, MJ, Prince, Luther V, Alicia Keys, Beyonce`, Def Leppard. Yanni, Kenny G, Keith Urban, Chesney, Dolly Parton, NSYNC, Boyz 2 Men, Black Crows, Alice in Chains, Foo Fighters, Goo Goo Dolls, Gary Moore, Doobie Bros, Foreigner, Styxx, Queen, Boston....like them or hate them, these are some of the hookiest artists of all time in a wide variety of styles in my opinion and what I've listened to for melody sense, infectious hooks, vocal delivery, and some darned good songwriting.
To think and write hooks, you have to surround yourself with hooks as a good starting point.
As for "unique" and the title of your post, I hate the word as it is misused in music and had been 50% of the time it's used. Unique to me means something different that is also something great that sticks out in a good way. The word unique these days is given to a large scale of artists who just plain, outright suck...period. When someone can't sing or play well...the downfalls of that artist are often times classified as "unique". "Unique and suck" years ago....wouldn't get you a record deal. Today, it's the standard norm for the majority of artists in my opinion.
Marylnn Manson to me is unique in his own way. I'm not a fan, but he's got a very different style to him with theatrics and a few good hooks with nice agression. KISS was unique, MJ was unique, Van Halen was unique. These bands were trend setters even if some may not have totally created a style or borrowed a bit from others that ended up being a fresh style over time. Unique to me is totally different, mind-blowing, inspirational and fresh while delivering the goods in a language that people can relate to while being accepted as also being really great at your craft. Instead, the word is more used for underachievers most times....so I stay away from that word unless someone I hear truly deserves it.
-Danny