How can i improve my talking skills?

i'm not very talkitive bcs of shyness..whenever i talk with any new person especially boys i feel very shy...i cant talk with them as my body shivers like i'm in a cold temperature while talking to them....whenever my teacher asks me to read the lesson or poems in the cl i cant do it and i would cry....i talk a lot in the cl with girls but if any boy observes me i would be calm....i cant give any speeches in the cl and my school on the special occasions like annual days,independence day etc.....my friends advice me to change this habit but i cant......i feel like i'm a dumb girl.....how to improve my talking skills??i dont want to shiver while talking with boy and many boys in my school try to talk with me....whenever they give a compliment on me and my work even i feel very shy to thank them....i dont want to be like this....i want to change a lot....pls give me any advices...thank you :)