Hi Suraj,
It depends on your risk appetite. Personally, I work around 0.05 lots per $200. In other words, If my account balance is $2000, and I have 8 – 10 EAs, my lot size will be 0.05 per trade. From there, I increase my lot size in proportion to my capital balance. Once my balance increases by 10%, my lot size will increase by 10% too.
Cheers,
Ilan