A fillet is a difficult place to start. Try laying a constant bead on top of a flat surface. Aim to create a puddle of molten metal and keep it going along the length of the weld. The tutorials have the basics, but where you see references to direction bear in mind with gasless wire it's better to pull rather than push.
Watch the puddle as you go. You want to melt in one side and bring the puddle to the other to melt it in too, I kinda make little "C"'s usually. Those welds look cold.....put more power to it.