UGH! help/tips?!?!?!?

Ok..i am really out going when i am around people i know...but when i am not with people i know well....i get really shy!!!! I hate this about myself and i wish i could change...any tips?!? Also, at our school we have to randomly stand up and make speeches about random stuff and everybodys is always funny and entertaining EXCEPT FOR MINE! ugh...any tips on tht either? like...any tips to make it more fun/ bettr?? I have asked this b4 and people say "just be yourself" but its so hard and i try to but it doesnt wrk!!!! pleeaaaasseeee help!!!!!!!!!!!!!!