I wantOver the summer holiday my Englhıs level increaseI want to improve my English.

For this ı canI will practice readıing ,writıing, listenıing and increase my studies.

APlease give my suggestions about improving my self ı can sguusentıon.

My English level is very bad.

Make sure you don't forget a verb in every sentence. Otherwise, I disagree, your English level is pretty good. Keep working at it!

I want summer holidayto improve my Englhısish level increaseduring the summer holiday.

Or: "I want to use my summer vacation to improve my English"

For this ıI can readıng , writınge, listenıng and increase my studiesy time.

can + verb does not use -ing verbs:

I can read [good books].
I can write [on langcorrect].
I can listen [to podcasts].
I can speak [with native speakers].
I can watch movies [in English].

AI am open to suggestions about improving my self ı can sguusentıon.

My English level is very bad.

I wantDuring this summer holiday, I want to improve my Englhısish level increase.

For this ı canThis includes readıing , writıing, and listenıing and increase studiesto English more.

Its a bit unclear what you want to say here

About improving my self ı can sguusentıPlease leave helpful suggestions.