1. Yes, this was a violation of proper technique. But when you learn how to do venipunctures, you'll learn that it's sometimes necessary to feel for the vein immediately before sticking. Many patient's have veins that move and roll, and if you just stick for the spot you felt the vein a few seconds ago, you might end up having to do multiple venipuntures. Ask your patients what they prefer: 1. several needle sticks, or 2. for a clean, gloved hand to touch their skin before they are stuck. Also realize that the chance of infection from a clean, gloved hand touching your skin and then a venipuncture being performed is extremely, extremely small.
Of course, the correct technique is to put on the tourniquet, find the vein, put on gloves, secure the vein with the non-dominent hand, swab the area with alcohol with the dominant hand, and then pick up the needle to perform the venipuncture with the dominant hand. This requires a little more preparation, as you have to have the alcohol pad opened and the butterfly set up before you start.
2. Most units don't have a policy against wearing rings and there is no evidence that they spread infection in non-sterile environments.
3. There was probably a policy about no fake nails/no chipped nails in patient care areas. Yeah, long fake nails kind of gross me out too. But consider that, as long as the nurse is washing their hands appropriately or wearing gloves during patient contact, you're probably protected. Still, if you find it warranted, you could send a letter to the department head and explain about this violation of policy.
4. If there was anything infusing into the IV, then yes, the infusion should have been stopped immediately and the IV shouldn't be used. But if it was a saline lock with no infusions and I knew the patient was going to be discharged and I'd have to take out the IV anyway, I would be okay with leaving the IV in for a short period of time until I got the DC order. Like a PP said, some floors have a really strict IV policy- where a patient must have an IV while they are admitted. So removing that IV might have meant the nurse needed to put another one in. Which if you were going home anyway, would have been a waste or time, supplies, and one of your veins.
You'll soon realize that the way you are taught in school is not at all like the real world. I wouldn't make a habit of pointing out these discrepancies to the nurses you meet during your clinical experience. Just notice them and ask yourself if there is really a potential for harm here. If there is, then report it to your instructor. But if it won't cause harm and is just a difference in practice, make the decision to perform the task "by the book" when you're in practice. But be prepared for a little bit of a rude awakening once you actually enter practice.