It helps to try to avoid thinking in terms of direct translation, but this is a good start! A good way to practice is to take your original phrase and break it down into simple components, instead of trying to tackle phrases that seem simple until you try to translate them.
いま、私は 日本語の書くかたを れんしゅうから、皆さん てつだって ください。
Now, I want to practice my Japanese writing, so please everyone help me.
When you think about it, "Now" is kind of unnecessary. If you want you could say 今回 (konkai, this time) or even 今日 (kyou, today). Either way, this sentence breaks down into two parts. Simply stated:
"I want to practice writing Japanese," and
"please help." There are a lot of ways you could write this. I'd like for you to try this on your own again without giving you the answer just yet, but here are some points to help:
kakikata means "way to write," but it would refer more to stroke order or writing something. "kaku koto" is more like "writing" as you use it here. However, "write in Japanese" would be 日本語で書く. The で particle here means "by means of" the same way you would say フォークで食べる, "eat with a fork." or バスで行く "go by bus." See how the meaning is essentially the same, but the words we use in translation vary?
れんしゅうしたいです is good! it's certainly one way to say what you are trying to get at.
the て form is "tenseless," that is, it does not indicate when the verb takes place. So there is no "past te form."
While tomii is right that (verb in te form)+くれる means "to do something for (me)," kudasai is actually a conjugation of kudasaru, a polite form of kureru,
and is used in requests. For this reason, you'd never actually use くれてください, since it'd be redundant. For physical objects, object + をください; for actions, (verb in te form) + ください. So "please help" would be...?
私の ゆめは 日本に 日本人と 話して、日本のことを ならう。
My dream is to speak to Japanese people in Japan and to learn more about Japan.
Again, break it down into simple parts. "My dream is" "Speak to Japanese people in Japan," and "learn about Japan." Even in English this is a little strange to me, as a dream would usually involve some sort of end goal, and "learn about Japan" is a little vague and ongoing for this structure. You could say it, but I think it would be better (and simpler) to limit your statement to "speak to Japanese people in Japan" or perhaps even "go to Japan and speak Japanese"
Another function of the で particle is to note a place "where" an action takes place. に actually infers direction, so while you could use it for 日本に行く (go to Japan) or 彼に言う (say to him), for "do X in Japan," you would want to use 日本で and not 日本に.
The reason for the ことです at the end of tomii's sentence was actually because the basic structure of the sentence is "My dream is..." and so it's essentially the same grammatically as 私の名前はボブです "my name is bob." As such, it needs to end in です, so that needs a noun, な-adjective, or for a nominalized verb. ならうこと is a nominalized verb. Take another stab at it; you actually weren't too far off.
ヱストミニスターだいがく いち年せいの生徒 で、コンピュターを 勉強する。
At Westminister University I'm a 1st year student studying computing.
So how far off was I, how could I improve what I meant and last but not least if I wanted to say 'would like to practice' can I say something like れんしゅうしたいです? I'm still beginner so please forgive any stupid mistakes I probably have made.
Thank you!
the hiragana and katakana for the "we" sound are actually not in use anymore; the way tomii wrote it is correct.
一年生 already means "first year student," so you don't need 生徒. Also, as you are currently doing something, you could use 勉強しています
This is another sentence where you have to think about the way you are organizing your thoughts. Tomii's sentence is actually a good example of using a clause to describe a verb (where a complete clause in the plain form can be used like an adjective): "I am a first year student (that is studying computers at Westminister College)"
Last thing that's not so important to meaning, but it's good practice not to mix levels of politeness, so if you start off finishing your sentences in です/ます, it's good to stick to that.
In all a good effort! I hope this helps.