Give basic exemption limit for all persons up to Rs.5 lakhs and charge flat 10 percent above that for all except companies for which it could be flat 20 percent. Dont tax agriculturists and charitable trusts. In case of any non compliance there must be severe fines with penalties of minimum twice the tax liability. This will encourage people to pay taxes promptly thereby bringing in entire income within tax net. This would shift the tax revenue as well. If this goes well then same for GST