Simple candles are a good lesson in material restraint. Wax, wick, heat, vessel, and time must agree. When one element is wrong, the flame reports it honestly.
Begin with small batches and plain materials. Scent, color, and elaborate molds can wait. A clean burn is more important than a dramatic object.
Wax and Wick
Beeswax carries its own faint honeyed character and burns with a firm glow. Soy and other plant waxes are common for containers. Cotton wicks vary by thickness and braid, and they should be chosen for the diameter of the candle rather than for wishful thinking.
Keep notes. Record the vessel width, wax type, wick size, cooling time, and burn behavior. Candle making rewards the same habit as cookery and joinery: observe, adjust, repeat.