Eighteen years old John was 'going'(to juz zaczyna byc troche 'nudne', moze lepiej...'on his way') to school 'like' (nie lubie tego slowa uzywanego w ten sposob,. wprowadzaj czytelnika w kraj wyobrazni, zeby chcial dalej czytac, moze ...just as he had done for the last X years) everyday. (przedimek, pamietaj o tych przedimkach) sSun was shining from (przedimek) early morning so he thought that (tu cos brakuje, ale ja bym to zrobila inaczej...'that it would be a day like any other') will be a good day.
When he 'walks' (zly czas, zle slowo..tutaj continuous..he was walking) 'to school' (niepotr, bo juz wiemy gdzie szedl) he found a (daj opis tej machete, mala, duza, ostra, ladna, stara) machete. He decided to take it because he likes movies where his favourite actors use 'this' (napisz machetes) to kill 'bad people' (moze daj lepsze okreslenie). 'After this' (napisz to inaczej...The rest of his journey was uneventful) 'without his way to school was normal' (niepotr). When John 'ends' ENDED his lessons 'in school' (niepotr) he decided to go on a walk with his girlfriend Alexis. (przedimek, pamietaj o nich) weather was really nice 'in' (niepotr) that day so they decided to swim in (przedimek) lake which was nearBY. 'their school' (niepotr- uzywasz slowa w ten sposob, zachowaj je na cos interesujacego). 'After this' (niepotr) THEN John decided to show Alexis 'what he found at the morning' (moze inaczej...this morning's find). She was delighted and 'curios' (blad ortog) because she 'have' (hello, tutaj she HAD) her own collection of machetes and sabers.
Alexis asked John 'that' IF she 'can' COULD polish his machete. He agreed 'with that' (niepotr) because he enjoyED watching Alexis polishing many things. 'because he had seen this before' (niepotr).
Suddenly five old men surrounded them 'and ask for' (napisz 'demanding' zrob to wiecej agresywne) cash. John couldn’t allow this kind of behavior. He 'reminded' (zle slowo, tutaj remembered, albo recalled') what his favourite actors 'were doing' DID with A machete and he decided to do the same. He made five fast slashes and in ten seconds all of theIR heads 'were laying' (zle, tutaj LAY) on the ground. (By doing this he had) saved himself and Alexis.
After 'all' (nie, napisz to opisujaco, 'the attack') he washed (przedimek) machete with his girlfriend and gave it to her (as a present?). She 'putted' (tutaj masz czas, niereg. PUT) it in (przedimek) 'honor place' (zla kol slow...place of honour) in her collection.
Dobre, ale pamietaj, ze jak ktos to czyta, to pisz to tak, zeby chcial 'widziec' co sie dzieje, uzywaj 'szybkich' slow jak piszesz o akcji.