Getting into Manipal Institute of Technology is not that difficult. Getting the top branches should be your aim. MUOET tests your speed and accuracy, most of the questions are based on formula and other small results and cases derived from that formula. Given that you are aiming for Computer Science (branch having a significant higher cutoff than any other branch), you should have all the formula on your finger tips. Your concepts should also be pretty clear.
There are some questions which can be solved purely based on the concepts. So make your concepts clear, especially in physics.
And I would give you a bit of advice, if you aren’t getting CSE, IT, ECE and Mechanical, there is no point joining this institute. Other branches have a much lower cutoff and most of the students in those branches aren’t that great. Placements also suck a big time in such branches (civil, chemical, ICE, IP, biotech, CCE, biomed etc.)
CSE is perhaps the best branch comparable to many decent NITs and placements are also top notch (mostly core jobs and very less IT/ITES jobs). Faculty is not that good but given the amount of MOOCs on the internet, any CSE student can learn whatever is being taught in the class. Also there are many coding competitions. Course work is also good. Many giant companies recruit from CSE branch like Microsoft, Amazon, CISCO, Directi, InMobi, Oracle, SAP labs, Citrix, Siemens tech, VMware, Dell, Snapdeal, SanDisk, Barclays, Amadeus lab, McKinsey etc. Average package is 5-6 LPA including MRCs (which are very less compared to core jobs) and without MRCs, average package in 7-8 LPA.