read your article, nice , great job!  but something still doesn't feel right, many places seem strange or simply wrong.

one thing you must understand is,, Chinese is a loose language in the manner of speaking, there are many variations to speak one same sentence for native speakers, that being said,when you write on internet or chat with friends you still need to be one of those variations in order to sound right and native-like.

here's my analyze:

你们好，这是在italki我第一个日(i assume you wanna say "it is my first <em>day（日）</em> in italki",right? but the grey area i just marked is nothing but "Chinglish"---we can't understand that, what do you mean? my first <em>fuck（日）</em> or something?),让我们希望可以交很多友（"let's hope blablabla"---still sounds like an English way of thinking）。

---here's my version of Chinese: "你们好，这是我在italki的第一天，希望能在这里交到很多朋友 :)"

在美国德州，我是一个大学生，现在学习生意(in english you are saying "I am an university student in Texas and currently studying business" right?, well, when you write Chinese, you shouldn't leave "in Texas" that far away from “a university student” as well. )。我跟我的弟弟住在，有私人的国际公馆(...)。这是我第二个学期，学习核算，生意电脑(business computer science?)，经济学，生意统计学(business statistics?)，和生意职业素质。我不喜欢数学，所以核算和统计学一点儿难，也一点儿没意思。我觉得别的三个课也没意思－哈哈，我应该只有路行癖（does "wanderlust" mean "i like to travel on foot" 我喜欢徒步旅行？, or it simply means "i enjoy wandering"我喜欢漫步? ）。

我一年半(from now？or before now？)在美国加州学习中文。那个时候，我住在蒙特雷。蒙特雷市  (missing "is"?)一个很美的城市，在海滩 （a city near sea？ say 沿海城市 will do）。每个周末我跑步了（了 always indicates a past tense），经过市区、海滩旁边、陆树下面。我很需要哪个（i really need a "which one" rest？？what the f..）休息，因为语言学校很难。每天，每个周，(Nein!! you might as well write “24/7” instead of chinese. LOL.. if you must indicate both "every week" and "every day",then say “连续X周以来，每天blablabla”should work)我们从早上八点到晚上四点学习中文。每个早上有一个下考(小考)，每个周有一个大考。学校以后（sorry,my friend,"after school" is not gonna cut it in Chinese, you should say "after school hours are over"instead.  放学以后）学生们需要学习差不多两个钟头。哪个(here we go again,,"which one"??what the h..)学校有很多压力，你总是觉得你需要接班(接班 means carry on with someone's work when he left the job, i assume you want to express "do extra hours" ,if so, please write 加班加点)，总是恐怕你会落空（always feel <em>"frightened</em>（<em>恐怕）</em><em>"</em> to "<em>dro</em><em>p</em><em> int</em><em>o</em><em> the emptiness" or "hit and miss"??  think again, you should</em> always<em> be </em><em>"</em><em>afraid（担心）"</em> of “（<em>落后）being left behind</em>”）。所以周末的时候每个学生  需要休息。一些学生打游戏机，一些去派对，我跑步了。我很喜欢了加州的自然天仙(godness or fairy??)，所以经常跑步了，游泳了，远足了，诸如此类。现在在德州，我觉得加州的天仙是更明丽，那是为什么我怎么喜欢那个地。 

当然，德州也有子明的天仙。德州的天仙是更干燥，更平(flat?)。这是我的老家，我在这儿生长了。圣安东尼奥市的日落很美，罗贝壳市风很强。在我的大学，我们有雪！在德州！我爱德州，爱加州，可是，那不是足够。我想看全球，从塞维利亚到上海，奥斯陆到约翰内斯堡。我要去中国，然后日本。

------PS: i didn't correct everything cause i don't think it matters that much.

the fastest way to be native-like and to avoid strange/wrong and non-native sentences is to absorb more native materials that you currently can absorb with ease.

either tv series , movies or native speakers can be the sorce, as long as you know how or when to use those materials are more efficient.