You can use the red axis arrows to control the snap to 2 directions. Use the tab key to flip the drections.
You can also sketch about what you want. Then add relationships to end points putting them on surfaces. Add relationships to lines to be parrellel to an edge or to follow the xyor z axis.
You can also use the 4 view window which lets you move a points relative to 1 plane at a time.
The tutorials also have some great info: HELP > SOLIDWORKS TUTORIALS > All SolidWorks Tutorials (Set 1)
There is one on 3D Sketch and one on 3D Sketch with Planes
The real trick to 3D sketch is to take your time and make sure that one line is fully constrained before moving on to the next.
Also, remember that in 3D sketch you can make a line PARALLEL to a plane. This little trick has saved me many a time.
As long as you can think "in 3D" you will not have any problem.
Remember that in 3D the "horizontal" and "vertical" concepts are meaningless (unless you use the "3D Sketch on Plane" workflow), being replaced with "Along X", "Along Y", "Along Z". There are other goodies there too: "Normal to surface", "On plane" and my personal favorite: "Equal Curvature" between a spline and a surface.
Enjoy 3D Sketching. You will have fun, for sure!
Welcome to the forum.
I believe there is a good tutorial in SolidWorks on using 3d sketches. Have you tried that?
Thanks for your response guys.... I'm expecting the same in future too....