i miss u,Taiwan

今年(This year)的(Like "me->mine", using to represnt the belonging)八月十二號, 我去了台灣 // just suggest to tell the time more specifically 

那裡(There)有很多(many/much, using to emphasize. They are not necessary, but we often include them in our sentence)吸引我的地方 (In ur edition, u use 吸引(attract, Verb)力(power, noun), it is regarded as a noun, like a kind of invisble power. On the contrary, in my way, i think of  吸引 as a verb. Therefore, u can use it in different way!)

讓我有去台灣留學的想法-----!

(It gives me an idea that i hope that i can go to school over there someday in the future. Overhere, i think that u must be attracted by something, so it gives u an idea or desire to visit here again, so that's why i connect the meaning of last sentence to write this one to make them more coherent.) 

期待下一次再度造訪(visit, u can also replace it as 拜訪, but both of them are really formal way)台灣,,,!!

(I'm really looking forward to my next visit in Taiwan)

我要努力學習中文!!

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In my opinion, actually, i think u have already expressed the meaning u want to tell us. However, considering the coherence, u still have a lot of room to improve, but i think u will make progress if u keep typing more. BTW ~ i'm so glad that u have visited my place just few weeks ago and go back with good mood. Looking forward to ur next visit here in Taiwan !   

i miss u,Taiwan

八月十二號我去了台灣

台灣（很）有吸引力
我有一天想去台灣留學-----! （我想在将来的某一天，去台湾留学。将来のある日には台湾へ留学に行きたい。）

快點 再去玩台灣喔,,,!! （很期待，能再次去台湾玩。再度、台湾へ遊びに行かれてのたのしみです。）

我要努力學習中文!!