Dang that shell!

Alright. So this is hour 2 of my cross-contour drawing of my miniscule shell and I must say I am very frustrated. I can't seem to successfully create the rise and fall of the shell as well as get the grooves in as well. They must also get progressively larger as the shell widens and flattens out at the edges as well. And without the guides of edge lines to map out the basic proportions of the shell, I must say I am not getting the proportion very well, as I am trying to create volume, proportion, and very detailed contours every time I lay down a line - oh! and not to mention magnifying the shell in my drawing as well!! so with all these elements I am trying to master at once, I am feeling like I am definitely fumbling along and not being very successful at any of them yet! argghh! YET, I continue, and hopefully I will see by the end that this is all very rewarding training for my eye and hand. UNTIL THEN, I continue with 1 hour left........