In both types Listening and speaking modules remain exactly the same and there will be no difference all while Reading and writing will have some different variants,
  Listening
This module has no difference at all both Academic & General remain exactly same. Test will consist of 4 sections including 40 questions. Audio recording will be played for 30 minutes and candidates have to answer questions, on the question booklet. At the end of the recording candidate will get another 10 minutes to transfer their answers on the answer sheet. Test will be 40 Minutes long in which recoding will play 30 minutes and 10 minutes to fill the answer sheet.
Reading
Reading Module is totally different in both types, in IELTS Academic reading candidate will find reading passage through historical inventions, analytical text. While in IELTS General Reading is taken from a magazine, books and newspaper etc.
Many believes that IELTS General is comparatively easy to IELTS Academic, However there is a difference in their scoring, Academic IELTS you need to get at least 23 correct answer out of 40 to get 6.0 band whereas candidate must get 30 right answers to make there 6.0 band in General IELTS. Reading test duration is 60 minutes and there will be no extra time provided to transfer answer on answer sheet.
Writing
Candidate has to construct a report consist of 150 words for Writing task 1 in Academic IELTS and IELTS General Writing involves letter writing of same bracket of 150 words. Task 2 Remain same in both types which is essay writing of 250 words.
IELTS writing test will last for 1 hour and candidate must finish there writing task 1 by 20 minutes followed by writing task 2 in 40 minutes
Speaking
IELTS speaking test is exactly the same in both variants of it. Speaking test consist of 3 parts and will be end after 15 minutes. It has 3 parts which are as follows.
Part 1 is introductory part in which examiner will ask three to four question relating to any topic for instance they may ask candidate about their hometown or culture of their country.  
Part 2 is known as cue-card
What is CUE CARD?
Cue card consists of a topic followed by 4 questions and candidate has to construct a speech on provided topic in which they must cover the questions.
For example topic statement will be as follows with question of w Family (what, where, when. Why etc)
Describe a well-known you like or admire
You should say
Who that person is
What that person has done
What he/she looks like
And explain why you like do or admire that person.
Candidate do not have to talk exactly for 2 minutes,  you can make speech shorter then given time as long as you have construct relevant speech which covers all the questions in it.
Part 3
Part 3 called related discussion followed by cue card, in this part examiner will ask again about 3 to 4 question which mainly relevant to the cue card topic.