Types : Choose from Large cap ETF, Mid or small cap ETF, Debt ETF, Sector ETF, Bond ETF or GOLD ETF based on your risk profile

Liquidity: Choose an ETF with high trading volumes

Tracking Error: Choose an ETF with least racking error wrt underlying index

Price Difference wrt NAV: Choose an ETF with least price difference wrt NAV

Expense Ratio : Choose an ETF with least expense ratio

Not a Recommendation but few ETF to study and track

Motilal Oswal Nasdaq 100 ETF, HDFC Sensex ETF, Birla Sunlife Gold ETF, Nippon long term guilt ETF