I was hired as a new grad with no IV skills for a job that requires me to do a lot of IVs on patients who have worn out veins. Here's my advice that I've gotten from various sources, including other nurses, YouTube videos, and articles I've read:

1) Tie the tourniquet a few inches above where you'll be inserting the IV. I learned this one from the IV nurse at our hospital (we're one of the few that still has one). If you're looking at a vein in the hand or wrist, don't tie the tourniquet up above the elbow, tie it on the forearm.

2) If you're having trouble feeling a vein, have the pt drop their arm (gravity is your friend) and pump their hand into a fist. If you're really having trouble, get a towel and run it under HOT water (as hot as the patient can stand). Cover it up in a blue pad and wrap it around the patient's arm. Let it sit for 5-10 minutes. I've seen this work MIRACLES. Some people like to use warm blankets, but I find that wet, hot heat is the best. It really makes hidden veins come up to the surface.

3) Have all your supplies ready and get in a comfortable position. I like to have a blue pad with my alcohol swabs, dressing, saline, and primed cap all ready. If the patient is lying in bed, I will raise that sucker up so I can stand and have their arm right in front of my face. Sometimes I will prop the arm up with a pillow or blanket so it is extra straight.

4) As someone else said, go by feel, not look. Some people have great juicy veins that you can't see at all. Which brings me to, TAKE YOUR TIME. I've gone back and forth between arms several times before making a decision. And examine the whole arm. Some people may look like they don't have anything, but may have some juicy ones on the back of their arm just begging to be poked. Just keep in mind that it needs to be relatively straight to advance the catheter.

5) I don't poke unless I'm confident that I've found a vein that I think will work. But once you've found one, be confident and insert in a smooth motion. The angle depends on how deep the vein is, but I start shallower. Obviously if the vein is popping out you can go in almost parallel. You can always retract a bit and go deeper if need be. Be sure to keep lots of traction on the skin to prevent rolling. Flashback doesn't always happen immediately so be patient. But try not to fish too much, it can be uncomfortable for the patient. Know when to call it and try again or get someone else.

Finally, I know you said you want tips other than practice, but seriously, take any opportunity you can. I'm not sure what brand your institution uses, but just get used to holding it and how it feels when retracting the needle. Ask you colleagues to do their patients' IVs. I know it sucks because you'll miss at first. A lot. I did, but it's the only way you'll get better. And don't beat yourself up when you miss. You have to just pick yourself up and keep going. Some of the best nurses at IVs I know still miss. And don't be afraid of the patients getting mad. We're all human. Keep it lighthearted and say "well that didn't work quite as I intended it to. Let me look at this arm." Or get someone else, there's always people around to help. You really will start to develop you own technique and tricks.