Sugar just speeds up the initial yeast ferment - unless you're trying to activate dried (not instant) yeast it's not needed (and even with dried you can just whisk in some flour). Salt improves flavour and IIRC also improves gluten formation, but retards yeast action. Fats slow staling and improve moisture retention, but again retard yeast action (at least when used in large quantities for enriched doughs).
For regular bread I tend to use about 1-1.5% of salt as a baker's percentage (i.e. of the weight of flour), and 1% yeast. A glug of oil or knob of butter for fat, and hydration at about 55-60%.