Buy and sell in smaller quantities and at different time intervals. Try to trade when the liquidity in the pool is high. This will, by default, lower the slippage. However, slippage is something that can’t be entirely avoided. 

Or you can use our new slippage-prevention feature:

By preventing slippage, your order will get partially executed or cancelled if the price changes adversely.

For instance, if the price of the share is 60, your order will be executed at a price below 65. If the total order value doesn't fulfil below a price of 65, unmatched amount will not be deducted from your wallet.