Can you please suggest some Shoujo manga for me to read?

Gakuen Alice :D its one of the best shojou mangas out there! the manga is the best though i mean the animes good to but the mangas better :D and here are some others
Tokyo Mew Mew
Shugo Chara
Special A.
hope this helps
P.S. this picture is a picture of Mikan and Natsume (the main couple of Gakuen Alice) :)

*Rockin' Heaven
L-DK
*Usotsuki Lily
Kimi ni Todoke
1/2 Love!
*Barajou no Kiss
Pureblood Boyfriend/Junketsu + Kareshi
*Dengeki Daisy
Shinobi Life
Kyou, Koi wo Hajimemasu
Kimi To Koi No Tochuu
Boku kara Kimi ga Kienai
Iinchou no Himegoto
*Beast Master
*If there is a star by it, it means I highly recommend you read it sometime. :)

Ouran Host Club
Kaichou wa Maid Sama
His And Her Circumstances
NANA
Vampire Knight

Clannad.

I read 'Black Bird' thats really good. Its about demons and spirits and everything, its really good

The Melancholy of Haruhi Suzumiya. It's not a manga, though, it's an anime and a light novel series. The female lead, Haruhi, is extremely strong. She has godlike powers that can destroy the world, but she doesn't even know it. It's romantic sometimes, too. Like, Kyon has a HUGE crush on Mikuru Asahina. Little things like that. The plot isn't really heartwarming, though. In the point of view of the narrator and male lead, Kyon, here is the basic plot:
So, this psycho chick named Haruhi started at my school. She forced me to join a new club about stalking aliens and time travelers and stuff like that. Mikuru and Yuki join, and then the transfer student Itsuki. I want to crush his mortal soul into pieces. Anyways, I found out that Yuki is an alien, Mikuru is a time traveler and Itsuki is an ESPer, and they're all trying to keep Haruhi's freakish, universe-changing powers under control. And I have to keep her entertained with this world so she doesn't wind up creating a new one. Oh joy.

Yup.

Try Rozen Maiden.

Try Mamotte Lollipop :D
But it's not sad, it's funny. Maybe you'll like it ^_^

Sailor Moon manga