learn really good sounding phrases off by heart for the writing and just add them in wherever possible and also try and rememer phrases using complex grammar like the subjunctive and stuff like :
se io avessi 18 anni andrei ha una discoteca.
they are really impressed with things like that. or if your talking about family a good one i always use is:
penso che i miei genitori debbano darmi piu liberta.
simple things like that always gets you marks. learn vocabulary specific to the topics like if your studying the environment make sure you know words like inquinamento ect.
in your exam make sure the stucture of the writing is clear and it flows, thats suprisingly important! and also something i always forget, always put accetnt on the appropriate words, not doing that can already llose you a mark or two.
if you want to practice reading get something fun like topolino, my dad always has one lying around, the language is proper italian (not slang like comics here). they will keep you interested for longer!!
anyway the best tip i can give is to impress the markers, if you dont already know some, learn sophisticated language and phrases with reasonably complex grammar structures in parts, not all of it has to be like that, just a bit to impress!!!
hope this was helpfull!! in boca al lupo!!