Using the correct proportions of the different ingredients (wax, additives, fragrance oils, dye) is the recipe for success in candlemaking. It is even more so if you want to be able to consistently reproduce those successes candle after candle. And because most of the ingredients are used by weight (even the fragrance oils), it's a good idea to invest in a good kitchen scale.
There's no pint keeping a detailed notebook of all your experiments if you don't bother precisely measuring and weighing the ingredients you use in your candles!
When your experience grows, you will be able to judge by eye, at least for simple candles, the right proportion of each ingredient... but until that day, a small digital kitchen scale will be of a great help.
For example, it is traditional to add one ounce (+- 28.3 grams) of fragrance oil per pound (+- 450 grams) of paraffin to achieve a strongly scented candle. Fragrance oil is measured by weight as opposed to by volume like another liquid because, depending on the oil used, the density can be different (some fragrance oils are "heavier" than others, which can be seen when you pour: some oils tend to "sink" to the bottom of the mold).
A small digital kitchen scale capable of measuring weights up to 10 pounds (5 kilos) with precision will do the trick to weigh paraffin or vegetable wax, Vybar, stearic acid, fragrance oils and other ingredients. Also, the "tare" function (which substracts the weight of the container to give you the net weight) will make your life a lot easier.
It sould not be difficult to find a digital kitchen scale that suits your needs. If your local appliance store is a dead track, look online, for instance at Amazon.