I started doing snatches recently and I need to learn many things.
First of all, I'm a bit afraid of when we get under the bar. Precisely, I'm afraid of hitting my forehead.
For instance, let's consider this frame taken from this video of Oleksiy Torothky:
Of course he is a champion and won't make this trivial mistake. But if you see it, I think there are no more than 3cm from this head and the bar.
If you look at this frame of Lu XiaoJun, there is a little bit of bar swinging forwards. How much should it be?
There must be some measures or technique to avoid hitting the bar. I think it could happen very easily to me (especially because my coach told me to pull the bar straight as my instinct is that of swinging the bar forwards), and I've seen people who had this problem (for instance this). And for this reason I'm a bit afraid when I get under the bar, which I think increases the possibility for this problem to occur. But I think I need some 100% sure technique to avoid this risk to let myself be fearless :)
Moreover: do you look at the bar 1 instant before getting under it? I can't because it moves fastly. But if I should do it, I'll try to do it. Do you stop if you see the bar has not be pulled high enough?