Next, add the control medal right smack in the middle of the head, or directly over the point where the two guides cross.

On a side note, keep in mind the control medal will take up about a third of the head's width.

Next sketch the top line of the eyes. This goes from directly under the medal to a little over the horizontal guide.

About this point you may want to start erasing guides as they become unnecessary.

<= Here I've added the head fin, which balances on the vertical guide and overlaps the control medal a little past the inner section. (The remaining drawings ignore the head fin but just pretend it's there after this, k? ^_^)

I've also drawn in the eyes. Notice that they reach almost to the edge of the egg-shape/head/guide. For most of the guyvers their eyes are rather thin and squinty and Guyver1's are probably the largest O_o , unless of course you're drawing SD Guyvers, which is another mater entirely....