How tough is it to get into IIM Indore as I am preparing for IPM?

If you want to decide the toughness on the basis of the availability of seats then yes, it indeed is tough to get into IIM Indore. The seats available for the IPM program are 150. So the competition is pretty tough.

But in reality, the majority of the students just are writing the exam casually. Some students even give up after looking at the test structure, difficulty, and other confidence issues. So the ones who are serious about and have seriously prepared for the exam are competing with a much lesser number of students. 

IIM Indore makes around 800–850 calls for an interview for IPM, which means one of every 6 good candidates gets a call for an interview. Around the top 180 students get a final offer (main list + waiting list).

So probability-wise you have a good chance of making it into IIM Indore provided that you are self-motivated and well-prepared.