I've been a nurse for a little over a year. Started as a new grad in ICU. I would say it took 8-9 months to become somewhat proficient at starting IV's. Here's a couple of pointers that have been helpful to me.
1. Get into a comfortable position and have good lighting. I generally sit next to the bed.
2. Go by feel and not by sight. I have seen my share of nurses trying to start 20 gauges in the itty, bitty surface veins of the hand because they can "see them". Ultimately those little veins blow because they can't accomodate a catheter.
3. If possible, read the manufacturers instructions and suggestions for the IV equipment you use. A recent thread on this site regarding Insyte IV's made me aware that the hub of the catheter has to be turned 360 degrees before insertion. I wasn't aware of that, which made advancement of the catheter (once in the vein) more difficult.
Here's a link to the BD site that contains instructions and usage tips for all their infusion therapy devices. I have found this information really helpful.
We don't use the wheal method where I work. Most nurses would say "why stick a person twice??" I wasn't aware that this is evidenced based practice either? I can see how this method would make it harder for you to insert the IV, with a bump on top of the vein. Again, I would suggest you go by feel as much as possible. Are you permitted to start an IV without the wheal and then maybe advance to the wheal method as you gain more confidence and proficiency?