how to get better times

Hello everyone, I have a question.What should I work on to get sub 23 solves ? Here are my avg. times for each of the steps. cross ~ 4 secs f2l ~ 14- 15 secs oll ~ 3-4 secs pll~6-7 secs I know 2 look oll and 2 look pll and I do my cross on above. Please post your thoughts below...