I m only writing the content so here`s it:

dear (friend`s name),
hello! how are you? i m fine here.In this letter i`m going to describe my summer vacation.
 this summer vacation was the best .My parents and i went to(place`s name) *plz describe the place`s beauty ,the fun u had there etc.
I will be waiting for your letter.Until then pay my regards to uncle and aunty and love to* (their sister`s or brother`s name if they `ve any) 
yours loving,
your name

plz keep in mind that the `love to` phrase should only be used for someone younger*

2 3 2
plz vote as the best
dude dont put commas... i had my english test somedays back and the teacher cut 1 mark for putting commas in dear (name) and yours lovingly
hahahah that is some days ago