Decidedly different from PTE Speaking because - among other things - you are assessed by a human being and this fact alone changes pretty much everything. To be a “Good User” of English - which is what Band 7 in Speaking is - you need to display:
1. Good Oral Fluency
What is it? Oral fluency is our ability to speak fluently - never mind the odd grammatical errors - in the language under consideration. Oral fluency doesn't mean speaking fast. It means uttering parts of a sentence and pausing at the right places for the right length of time. It is the natural sense of rhythm, which we are all accustomed to. If you speak without pausing where you should, it may actually be defeating your purpose. Oral fluency is very important if you wish to achieve a high score. Grammatical accuracy at the cost of linguistic fluency will never fetch you high bands in speaking.
Yes, inability to pronounce correctly will negatively affect your score. Just speak naturally and ensure that your pronunciation is free of Mother-tongue Influence (MTI). When the test is being taken in India, the benchmark for speaking will remain the average Indian speaking in English. As long as you are audible and intelligible, pronunciation should not bother you much. And by the way, they accept the British as well as the American pronunciations. Just don't indulge in slangs/colloquialisms.
4. Ability to use Synonyms
And to do so quite easily. Thus avoiding repetition of the same words, phrases and even sentence structures. IELTS - and this is true of the test as a whole - does not ask you to memorise 'difficult' words & phrases. You are not expected to digest a long list of tongue-twisting, gut-wrenching and teeth-rattling words. On the contrary, the need of the hour is a regular use of 'uncommon' words. Rather than 'great', awesome' or even 'wonderful, maybe 'pleasant' experience is a better way of putting it. Along with all this, you need to be relevant as well. Finally, your answers should be neither too short/abrupt-sounding nor rambling/meandering/too lengthy.
A general ability to address the question/s asked. Don't beat about the bush. Come straight to the point and always elaborate after you have given your answer in the first lines. The length of your answers will differ in accordance with the complexity of the questions asked. Generally speaking, Part 1 questions are simpler than those you will be asked in Section 3. The more focused and crisply-explained your answers, the higher you score in the Speaking section. Also, questions which are specific require a different answer than those that demand a general reaction from the candidate. 'Do you like shopping?' is qualitatively different from 'Do you think shopping as an experience during your parents' time is different from what it is now?' Your response should acknowledge this difference.
Now, I'm sure all this sounds rather daunting. Happily such is not the case. Don't bite more than you can chew: break the entire Speaking module into a number of small sessions. And regular practice - just a little (15 minutes) every day for a month or so - should do you a world of good. Excellence, after all, is nothing more than a Habit.