Another comment is about your conjunction in your composition, which is quite common in both Chinese and English articles, right?
e.g. : 我希望可以工作喺香港。我喺銀行做嘢。我去咗香港五次，有好幾親友。我有兩個姨媽住喺香港，佢哋住喺九龍塘同埋跑馬地。我表妹真係好叻，佢想係一個註冊護士。我表第係好叻，但係佢真鍾意玩電子遊戲。我表哥而家做財會(original)

i might change a little by adding some conjunction, such as Conj.
我希望可以喺香港工作，而我目前喺銀行做嘢（in boston）。

我去咗香港五次，在那裏有好幾個親友。其中，我有兩個姨媽都住係香港，分別住喺九龍塘同埋跑馬地。至於我表妹真係好叻，佢想成爲一個註冊護士。同時我表弟都係好叻，但係佢太鍾意玩電子遊戲（真should be changed into 太 in order to express negative here）。仲有，我表哥而家做財會。

廣東話/粵語 - Introduction

大家好，
我叫建業，伊個係我嘅中文名。我識講一點點廣東話，因為我爸爸同埋媽媽識講廣東話。我婆婆識講廣東話同埋潮州話。我婆婆唔識講英文，佢英文講得唔好。我想提高我廣東話因為我想可以同我婆婆傾計。我而家住喺波士頓，我婆婆住喺多倫多。

我希望可以喺香港工作。我喺銀行做嘢。我去咗香港五次，有好幾個親友。我有兩個姨媽住喺香港，佢哋住喺九龍塘同埋跑馬地。我表妹真係好叻，佢想成爲一個註冊護士。我表第亦係好叻，但係佢太鍾意玩電子遊戲。我表哥而家做財會。佢冇女朋友，但係我希望佢可以搵一個女朋友，因爲佢妹妹已經有一個男朋友。佢係有錢人同埋佢都係好叻。我朋友住喺好多地方，比如，旺角，太子，中環，半山區，上灣，跑馬地同埋元郎。佢哋都係有錢人同埋屋企好大。

我廣東話麻麻哋，但係我想提高我嘅詞彙。係噉先。拜拜！

Comments:

Your cantonese is good enough, and in fact quite see ppl write cantonese articles much : )

However, there were some sort of small corrections marked in red above, for example, sometimes you could write "係" as “成爲” ，coz "to be" is translated in “係” in cantonese. （佢想成爲一個註冊護士 rather than 佢想係一個註冊護士）。Besides, 但係我希望佢可以搵一個女朋友，因爲佢妹妹已經有一個男朋友 , not find any mistake in grammar but in logic. Is there any reason that you brother need a GF owing to his sister ? :)). 

But in all, your cantonese is not bad at all. The only problem might be your spoken cantonese :).. still have a long way to go . 

Cheers.

廣東話/粵語 - Introduction

大家好，
我叫建業，嗰個係我嘅中文名我中文名叫建業。我識講一點點小小廣東話，因為我爸爸媽媽都識講廣東話。我婆婆識講廣東話同埋潮州話。我婆婆唔識講英文，佢英文講得唔好。我想提高我廣東話因為我想可以話我婆婆同我婆婆傾計。我而家住喺波士頓，而我婆婆住喺多倫多。

我希望可以工作喺香港我希望我可以喺香港做野。我依家喺多倫多噶銀行做嘢。我去咗過香港五次，有好幾個親友。我有兩個姨媽住喺香港，佢哋分別住喺九龍塘同埋跑馬地。我表妹真係好叻，佢想係一個註冊護士。我表第都係好叻，但係佢太鍾意玩電子遊戲。我表哥而家做財會。佢冇女朋友，但係我希望佢可以搵一個女朋友，因爲佢妹妹細妹已經有一個男朋友。佢係有錢人同埋佢都係好叻。我朋友分別住喺好多地方，比如，旺角，太子，中環，半山區，上灣，跑馬地同埋元郎朗。佢哋都係有錢人同埋屋企都好大。

我廣東話麻麻哋，但係我想提高我嘅詞彙。係噉先。拜拜！

其實已經好好，繼續努力，就似你評論講噶一樣，多D同人交流，甘你先回有所提升！