grammar - Different ways to show intention to do something

How can one say "I am going to", express intention to do something in the future. I know some expressions such as:

たいと思う - 　I'm going to/ I want to

ましょう - I will/ Why don't I

しようと思う　- I think I will

しようとする - I'll try to

するところ - I'm about to

つもり - I plan to

する予定がある - I have plans to

する気がある - I feel like

ことにする - decide to

まいとする　- I'll try not to

まいと思う - I think I won't

Do I understand what they mean correctly? Which are better to use when? What is the difference between similar expressions (予定　and　つもり) ?

Answer

Your definitions were mostly OK I think.

I'm not an expert on grammar, so take this as a temporal answer until other people answer, but my interpretations thus far are...:

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  ～たいと思う means "I think I'd like to...":

  
  

  
  

  本を読みたいと思う "I think I'd like to read a book"

  
  

  
  


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  ～ましょう means "let's do..." (polite form):

  
  

  
  

  本を読みましょう "Let's read a book"

  
  

  
  
  


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  ～しようと思う means "I think I'll...":

  
  

  
  

  本を読もうと思う "I think I'll read a book"

  
  

  
  


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  ～しようとする means "I'll try to..." as you said:

  
  

  
  
  

  本を読もうとする "I'll try to read a book"

  
  

  
  


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  ～するところ means "I'm about to..."/"I'm at the point of..." or "place for (do)ing...":

  
  

  
  

  本を読むところ "I'm about to read a book" or "place for reading books"

  
  

  
  


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  ～つもり means "I intend to", slightly less formal than ～予定がある I think and is less likely to be used in business etc:

  
  

  
  

  本を読むつもりだ "I intend to read a book"

  
  

  
  


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  ～する予定がある "I have plans to" as stated:

  
  

  
  

  本を読む予定がある "I have plans to read a book"

  
  

  
  
  


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  ～する気がある "I am of a mind to":

  
  

  
  

  本を読む気がある "I am of a mind to read a book"

  
  

  
  


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  I think ～ことにする translates differently depending on the context, but that it generally means "(will) go with (do)ing...":

  
  

  
  
  

  今週こそは本を読むことにする "I will go with reading a book this week"

  
  

  
  

I'm not sure about ～まいとする and ～まいと思う. I think the difference between ～予定がある and ～つもり might need it's own question.