When we have an actual technique to work with, such as tonglen, this will only work in the context of intention and repetition. There is no magical panacea, a technique that you find or someone gives you that just kind of magically works. It is by the sheer weight of accumulation that it works. How many times does a top 100 golf player hit a ball with a club? Or the concert pianist hit the piano keys? Good spiritual technique is not the slightest bit different – it emerges through immense repetition.