That is a great question. One of the first things to understand is that workflows can change depending on your type of shot. When it comes to some of my more physical shots I didn’t animate in stepped, because it gives a false sense of weight and motion. For those, I animated the shot in spline from the blocking stage. This allowed for me to quickly see the action in motion and get the right feeling for the shot before it goes too far. With acting shots it can be very helpful to block it out in stepped so you can see if your poses are communicating exactly what you intended. The way I help the transition is by keeping in mind how poses will flow from one to the other and keeping in mind the timing and spacing of the action. Following your reference will help in finding exactly how poses flow between one another, and you can exaggerate from that base of understanding. If the computer has to do too much work to interpolate your action, you will tend to get unexpected results. Defining your actions by laying down more keys has been a technique that tends to work well for experienced animators, but will backfire with students because experience plays a big role in understanding timing and proper spacing of actions. Depending on your skill level you may want to lay down less information in your blocking stage and move to splines quicker to allow for your animation to be more flexible and easier to work with. Moving to splines quicker also allows you to trouble shoot anything you may have missed much earlier before laying down too many keys. When blocking a shot in stepped there are a few techniques that will keep you from getting unexpected and unwanted results. Keeping your graph editor open while animating will allow you to see bad rotations and and improper spacing early in the animation process, so learn how to read your curves. Flipping your curves from stepped to spline in early passes of your shot will also allow you to spot sections that will end up causing you problems in later stages of your animation. A frequent problem in the transition between stepped to spline is bad breakdowns and inbetweens that you set. A tool called the tween machine is very helpful in creating proper inbetweens and breakdowns. You will still have to work with the pose that you create with the tool but it will give you a good base to work from to build your pose without creating rotation issues. I hope some of the advice here will help make the transition from stepped to spline easier for you. Best of luck and feel free to send me a link to your work if you are looking for a crit.