→ Any:

• Any is used in negative sentences.
• Any is used in the doubt sentences with negative meaning. Any is reserved in a sentence with - if, without, whether, much/many, doubt, doubtfully.
  Example:
  Without your support, I have no means.
  = Without your support, I have any means.
  = If you don't support me, I have no means.
• If a sentence has - "hardly, scarcely, barely, seldom", then the sentence is negative. In such sentences, any is used.
  Example:
  I hardly know that he has any friends here.
  He seldom brings out any idea about such matters.

→ Many:

• Many is countable plural and used in affirmative (positive) sentences. It is more than "some", "any".
  Example:
  We can see many people packing the stadium today.
• Types of many: (i) Many + plural noun
  Example: Many students are gathering for the agitation.
  (ii) A + great (not used in sentences, but suggests a strong meaning) + many + plural noun
  Example: A many students are gathering for the agitation.
  (iii) Many + great (not used in sentences, but suggests a strong meaning) + a + singular noun = plural noun
  Example: Many a student is gathering for the agitation.
  (iv) Possessive + many + plural nouns
  Example: My many friends are selected for AIPMT.
  (v) Very + many + thanks
  Example: Very many thanks for your achievement.

→ Any/Many in Negative sentences:

• Any in a Negative sentence with countable plural = no + plural noun without any
  Example: I don't have any friends here.
  = I have no friends here.
• Negative with singular countable use Any
  Example: I don't have any friend here.
  
• Many in a negative sentence with countable plural ≠ no + countable plural
  Example: We can't see many oranges today in the market
  ≠ We can see no oranges today in the market.

→ Negative sentence with uncountable NOUN (Much):

• Much is always used before a NOUN of Quantity
• Much = Many = Plenty in meaning
• Avoid usig of Much in affirmative sentences
• The Quantity is larger in the case of Much
• We can use Much in negative sentences in the following steps:
  (i) Strike out the Negative word from the sentence so that it becomes positive
  (ii) Insert littlein the positive sentence
  (iii) If so, we can use Much in the negative sentence

→ Negative sentence with uncountable NOUN (Enough):

• It means SURPLUS (more than what is required)
• Used in both positive and negative sentences
• Can be used both before and after the Noun
• Can be used before countable plural
  Example: I have enough petrol in stock for this summer
  = I don't have enough petrol in stock for this summer.

→ Little = Few = No:

• Little is used before the Noun of Quantity
• Few is always used before Countable Plural
• No is used before Plural/Singular Noun
• Little = Few (almost negative in meaning)
• Little = NO but NO ≠ Little
• Few = NO but NO ≠ Few

→ a little/a few = SOME:

• a little indicates unknown Quantity
• a few indicates unknown Number
• Example: Lend me a little salt.
  = Lend me some salt. (Here, 'some' is used in Imperative sentences, as request)
• Examples:
  We have a little salt left in the kitchen.
  We have a few books left in the library.
  

Let's see the difference using examples:

• Go and buy some salt. We have no salt in the kitchen.
  It is different from
  We have little salt in the kitchen.
• I feel lonely. I have no friends here.
  It is different from
  I have few friends here.

English is WEIRD. It can be understood through tough thorough Thought though.
- Unknown