Like most things ... practice, practice, practice!
Perhaps make a place mat or two or some mug rugs to practice on? Or even just sew some scraps together and sandwich. For practicality, I like to make something though, instead of just sewing scraps that I intend to toss.
For me the SITD foot made a huge difference in staying in the ditch!
Also, go with a finer thread, as any mis-stitching is less noticeable.
If you don't feel good about SITD, what about stitching 1/4" (or less) from the seam line?