I am non malay, but i managed A2 in my Bm paper.
so what i did is....

1. Mixed with lots of malay ( to speak the language and put it into practise ) remember, dont speak broken bahasa.

2.Get a good peribahasa, simpulan bahasa dictionary. - this can helps you to do better karangan. It helps to score more points when you have nice peribahasa, simpulan bahasa and bunga bahasa in your karangan.
( this should give credit to my BM tuition teacher, who enlightens me on these )

3. enrol in a tuition centre for the language. They have lots of good exercise. test preparations for you. And you get some tips too.

4. Read Bahasa newspaper. Read as in, absorb how they composed those words, the sentences.

5. enjoy the language.

good luck !

To improve your Malay, first get some children's book and read about 30-40 of them. Then get a revision book that has a complete guide on Malay grammar and read it. Like how to use, me, men, meng or when to  -i, -kan, and so on.

Study all the grammar rules carefully.

Then take some adults books or articles. And read then. Don't read think books with fine print. Get something fairly nice, big fonts and not too thick and read about 40 of them. By now you should get A for Malay.

Don't ever read Malay newspaper, that kind of Malays is 1/3 crap, 1/3 not suitable for karangan sytle and 1/3 english words that has been Malaylised.

Grammar is the most important and next comes vocab(a good vocab means you do not repeat word mean your marks will shoot up alot cause it will sound more interesting), lastly comes style, that one, the more you read the better you get.

I still remember how my primary teacher(which in return, i tuition under her for 3 good years) groomed my BM from dustbin to a standing ovation of honor to her. First, she forced me read a lot of Malay language materials(includes books, newspaper, and anything which I can find, even magazines). From there, I proceeded to own a malay dictionary, and simpulan bahasa and peribahasa collection of books, which improved my vocab tremendously. For the essay, I started of with fill in the blanks, proceeded with simple essay. From there onwards, she will gave a random question, and told us to use our own creativity to write a essay from there. She will correct the error that we made, and in return, we will do the correction(writing down the essay from start to end) again.Failing to do her homework, you will be punished by caning on the spot, and humiliated in the class but her method of teaching is one good way, and at least we(the batch that tuition under her) gained a lot from her.

My advise to thread starter, write more and give it to someone who have experience to check for error. From there, learn your mistake. And always have the good old buddy, dictionary with you. Malay language is a wonderful language to learn with, especially with bahasa kiasan, simpulan bahasa and peribahasa. A lot of good essay comprise of this thing. It never turns down the reader to not to read it.

and to newcomers to Malay language, I highly encouraged you guys to learn to bersajak, berpuisi, berpantun, berbahas, and etc which is part of Malay language learning skills. Those mentioned above are a rare scene nowadays. to her for guiding me on those stuff, and if any one of you needs some tips or wants guides to start, I would be gladly help.

find me.. im a good BM tuition teacher n comfirm for improvement.. haha.. actually i think dat BM is not same wif English. those grammar stuff is not same... BM is a lot more easier actually..  i think if u r a malay... u speak malay at home rite? de more u speak den de better u wil become... but note dat speaking is nt same wif writing.. so u must noe dat some of de words is not suitable in writing...

get 1 good dictionary to help u.. i wil recommend KAMUS DEWAN .read more essays n newspaper... btw may i noe u r studying for PMR o SPM? let me know den i'll gv u a better way on it..

hope dis can help u..

You can try reading books/magazines like Dewan Masyarakat or Dewan Siswa to improve your BM.

For english,try reading Reder's Digest.

I did that and my grades improved.