Break piles you are on that contain your dead colour. Attack tenuous piles, even if they are only single squops. You'll then get two shots to one, a huge advantage. Concentrate on getting the flat winks, as they are more mobile. Take your time, and try to keep a guard handy in case things go wrong.
Opportunism takes many forms.
Things happen that interrupt your current plan. Deal with them and, unless the situation has changed a lot, go back to the plan. If an opponent's next shot is forced, you can attack another wink of that colour at no risk. If an opponent goes off, you can approach and squop that colour before it gets to play again. If your opponent has a tenuous pile you can gain at least time by hitting it on approach shots.