Getting near insects requires a lot of patience. Its always good early morning or late evening but light is sometimes a problems so you will need to use flash
Picking a place where insects favour is a good place to start, you can just wait without moving a lot. Move slowly and take photos as you approach once they are in focus. If they are feeding they will be fairly stillThe other thing is not to cast a shadow on the flower/insect otherwise they will be off so where you stand is just as important
The abundance of insects has been greatly reduced over the years so if you find a good spot then go back throughout the year as insects emerge at different times.