Hire a lot of helpers. Students are often cheap. ;-)
Seriously though, in my view it's rarely viable to do load testing manually beyond relatively low user numbers - and even then it's very hard to get a repeatable workload.
I have resorted to this sort of approach occasionally in the past - get all staff in the organisation who will be using a new system to work overtime and get them to process a prepared list of test transactions. The logistics can can be very difficult though - especially if you need to repeat the tests. I'd generally advocate automated testing tools if at all possible.
Thanks for earlier reply.Still I am not satisfied with the answer given to me for my this query.I want to know what is the step by step process to check the application performance by putting load on it.How do you collect matrices and data which could tell the performance of your application.Let me tell you my way of doing it.Like we can say 100 users to sit around in a network and use the application simultaneously by doing all sort of transactions defined by the system.Then you can increase the number of users by 100+ making it 200 now.and then you check the performance of the system.
But I am not satisfied with this process as it can not give me matrices I want for performance checking as it is all based on perception.Your perception tells you how the application's performance is when you are increasing number of users.So is there other method in manual testing for checking the performance of the application.
My second question is how will you manually test a particular process which ends in suppose two three days.Means if you input some data it takes two days for doing all transactions and then giving you output.Like in banking and share market software some processes takes couple of days in finishing.How can you test that sort of process manually.