Real meaning of ーようにする??
 

The first time I met ーようにする I was happy because we have in my language (Italian) the same noun, same preposition, same verb in the same form so I assumed it had the same meaning of my language. It was a relieve because that form can assume so many different meanings that are not easy to study one by one. In fact when I moved to the USA I was in trouble because I didn't know how to translate it (and we use that form alot).

When I started studying on textbooks and arrived to this grammatical part I was disappointed. What I thought was all wrong. All the textbooks I have translate it as "try". But the meaning I was giving to it is not just "try". I will give some example (literal translation from Italian, so wrong Japanese). We can use it for commands like 犬に今夜餌を与えるようにしろ　(tonight feed the dogs); it can be used for requests 仕事に1時間ほど前に行くようにできませんか　(could you come to work 1 hour earlier?); or even for instructions ３Ｄ映画をよく見られるため、めがねを使うようにする べき　(to see well a movie in 3d you should wear glasses). None of those actually translate with a "try". Even when my mother used to tell me やさいを食べるようにしてください it was not really a "please try" LOL.
Anyway since then I started treating ーようにする・ーとする・－てみる all the same as "try".

Last month I bought a new textbook and this one gave a difference between the first 2 forms. It said that ーとする is meant for trying something at the moment, while ーようにする is used more like a continuous time (such as changing a habit). Still not the use I thought it was, but at least I was given a difference.

NOW...last night reading a book I found this phrase: ナイフを取って出すと、刃先を婆さんに見せるようにし て猿ぐつわを外した。 I see this in phrase a usage of ようにする similar to the one I am used to and not a "try" meaning: pulled out the knife and making sure to show the blade to the old woman, he took off her gag.

So how do I treat it? As a simple "try"?
I know it is a weird question, but I hope it makes sense to you...too LOL.

You're confusing two different grammar points. One of them, you attach ようにする to an entire verb. The other, you do the volitional form (よう form, I guess you could call it) and then attach とする. Look at the difference in the verb in these two examples with an ichidan verb:

食べるようにする in order to eat
食べようとする try to eat

Now, it's mega-important to realize the difference in form because if you use a godan verb like 飲む:

飲むようにする in order to drink
飲もうとする try to drink here, there is no よう at all because the volitional form of a godan verb does not have よう

Look at your examples and their English translations to see they aren't "try" sentences. 行くよう、使うよう, they are "in order to [be able to]" sentences. 行こう and 使おう would be "try" sentence forms. Volitional form, and no よう, since neither is an ichidan verb.

I will try to eat sushi
すしを食べようとする

In order to eat sushi, I use chopsticks.
すしを食べるようにはしを使う

I didn't write the whole thing, just used ー, but I am not confusing them. In the books I have they treat both ーとする and ーようにする as "try to do something". The way I know it is "in order to drink" should be 飲むように without する.
Give me few minutes to go and get the examples the books use...

From the last book I bought (the one that explain the difference).

忘れないように書きます I will write it so (in order to) I won't forget.
忘れないようにします I Will try not to forget
たまごを食べないようにしています I am trying not to eat eggs.
うそをつこうとしました I tried to lie.
And so on...

But the fact is that every book ties ようにする to "try". What I would like to find out is if there are other meanings...if it is the way I think, actually even "try" doesn't translate the exact nuance of ようにする. Actually the whole translation "in order to" doesn't really represent the whole concept of よう (way). But of course I am talking with knowledge of how it works in another language...but if I am true and in Japanese is like Italian, sorry, but in English there is no way to translate ようにする because it assumes many different meanings (trust me, I have tried and tried...and still can't express my real feeling coz I can't use ようにする in English in many cases).

Sorry I had missed this part. Let me try to explain how I see it...then of course a native Japanese will correct the way I see it. I use a phrase as example:
犬に今夜餌を与えるようにしろ trying to literally translate would be "tonight do in a way that you feed the dogs". The nuance of this phrase is: no matter what else you have to do, you do find 5 minutes and you feed the dogs.
The example about my mother やさいを食べるようにしてください even though looks polite implies I don't care however you will do it, but you are going to finish you veggies or you get in trouble.

犬に今夜餌を与えるようにしろ sounds pretty awakward to me. 「今夜こそは犬にエサをあげるようにしろ　ＯＲ　しな さい」 would be closer in meaning to what you said.

やさいを食べるようにしてください is a valid sentence but it doesn't mean what you said. It doesn't talk about just today or a particular meal. It's something a doctor or mom would tell you if you don't consume enough vegetables on a day-to-day basis. It's really saying "(Please change your diet and) try to eat more vegetables."

～～ようにする most often means "to make an effort so that ~~ would occur".

Thank you. I guess both our languages see it the same way, but use it in different occasions. We use it a lot also in the immediate time and for a one time only occasion, while it seems in Japanese it involves more a habit or something on a longer period of time. We use it a lot to avoid using the imperative that can be rude (like my example of my mother) and it appears as a form to avoid mentioning negative consequenses. Even the example I put up about getting earlier to work it would be a polite request that hides an order. Even in organized crime they use this form (for example もう話せないようにして which is an order given to someone to kill someone else).

I guess I will have to go to google and see various example to learn in what way it is used in Japan. But at least now I know it is not only "try" like my grammar book taught me.

I think you're still confusing it. With 〜ように, you are not trying to do the 〜 at all. You are doing something else so that 〜 will occur. You aren't making an effort by doing 〜at all.

For example,
雨が降るように雨乞いをします。
So that it might rain, I will do a rain dance.

You are not trying to rain. You are merely doing a dance, and your goal is that hopefully the dance causes it to rain.

Hence 〜ように should not be thought of as trying to do anything. The closest it can be to your "try" attempts is to "try and cause something to happen" rather than "try to directly do something."

But that was all my point. I wanted to know if it had another meaning apart from try and Masaeguさん confirmed that it does. All the example I wrote would NOT work if you translated them with "try". I wanted to know if those examples would work in real Japanese and they do.
ようにする has no attempt in it. Maybe (if grammatically correct) ようにしてみる has an attempt in it. But on the other hand, it doesn't even have a purpose in it, for that you should have ようにするために. The way I used it in my language for 30 years and that Masaeguさん confirmed is a method. You do do something by means of which you obtain something else. よう means "way", not in order to or try. A way of doing something. Sometimes in English can be translated with "try", sometimes with "in order to" and other times (like the phrase that was on my book and it's quoted in my opening message) "to make sure that". It is always different.

I hope this will help you better. I got a 5 year old daughter and I am trying to teach her Italian, but she is not that good yet. The other day before going to bed I told her (in Italian) after I go to bed 音が立てないようにしてください She stared at me and said ようにして?? so I repeated 音が立てないでください. The meaning is the same. But while with the second phrase I ask her please to try not to make noise, with the first phrase I ask her please to make a strong effort not to make a noise.
Now, by what I understood from Mesaeguさん, in Japanese it is still a request. While in Italian it becomes more an order...I do want that effort to produced the result I asked. This was mainly what my question was revolving about. If they have the same use and it seems they kinda do, with some different nuances.

I really hope I am making myself understand. I don't mean to prove you wrong, but I guess you didn't understand my question from the beginning.

I probably didn't understand it then. :)