Fail to prepare, prepare to fail. Preparation is key in a lot of situations, and Medicine as a whole is one of those situations. Having a solid plan, thinking it through and making sure you have everything ready beforehand will save you a lot of trouble. A good way to do this is through visualisation of the procedure. When I get kit ready for cannulating, I picture myself applying the tourniquet, finding the vein, cleaning with the swab, putting some gauze just distal to where I’m going, inserting the cannula (with or without taking bloods from it), removing the tourniquet, applying the flush and then sticking it down with a dressing. While doing this, grab the equipment for each bit as you think of it, and always take a spare cannula!
You only ever forget a flush once…