Though there may be tutorials available, including some supplied by PTC and several university sites, what i reccomend is that you try tutoring yourself with the follwing tips.
i had come accross the same issues long back but perseverence and some exposure to CDRS allowed me to overcome the issue.
take a complex surface like a Harley tank / any other demanding surface.
check whether there is any axis of symmetricity. If yes you could model only half and mirror the rest.
before starting visualize the minimum number of curves on that surface which when shown only as curves will generally give an idea of the final surface.
once you have these in your mind draw them such that they are on planes and any curves ending at the plane of symmetry should be normal to the plane of symmetry.
Ignore any plane surfaces, which you can always overbuild and merge later using a merge, then trim and then merge with a third surface for the gap.
now use any set of 4 sided curves to build a surface ( preferably the largest surface are optimal set in terms of the surface created) using the surface / advance/ use boundries command.
then split parts of the curves along the edges of the surface created and in the curve feature window use the option of tangent or curvature connection to the bounding surface.
use 3 curves and one edge of the created surface earlier to make another 4 side surface and in the feature use the option tangent or curvature.
Then merge the surfaces and repeat the whole process imagining the merged surface as the first surface and building the second one.
In case you probably end up with a three sided surface after a while, try to make it of the smallest area and then use boundries with 2-side as curves and the other 2 as 1-curve and 1-vertex. Be sure that the vertex is not a vertex of a curve but that of the surface. (you can always verify this using query select)