One of my friends likes to power farm with Diana until level 6 and then lane gank bot lane. I've watched her do this idk how many times and it works every time seeing as bot gives you the greatest chance of success with there being (most likely) two forms of CC assisting. This is at low-mid Plat and it works near 100% of the time. As for the build it's just as everyone has been saying in prior posts. Just remember as soon as you throw out your Q you can immediately R instead of waiting for Q to land and then ulting. More burst quicker giving the enemy less to time to potentially flash out.