Gin is one of the most difficult spirits to develop without a very methodical way of developing your gin.
There are four crucial processes in developing a new gin - and 128 ways of making Gin!
1. Determine and characterize the aroma profile or style that you would like your gin to reflect.
1.1. Identify the base aromas (Using the gin nosing kit will greatly assist you)
1.2. Determine the relative intensity of each aroma. Start with a simple 3 point scale such as:
1.2.1. Feint or very subtle notes
1.2.2. Distinguishable without problem
1.2.3. Loud and bold notes
2. Identify the various botanicals that will produce the required aroma profile.
2.1. Luckily most of the base aromas reflect in selected spices and herbs and correspond to well know names (i.e. the chamomile base aroma comes from .... yes, you're right: Chamomile! On the other hand, liquorice flavor is also mostly in Aniseed and Liquorice root also imparts sweetness to spirits. Have a look at (the diagram here below), what typical herbs and spices you can expect to find in gins.
3. Determine the ratios of the spices/herbs that would provide a balanced end product - it is very easy to copy someone else's gin ingredients, but you might end up with a totally unexpected results that doesn't reflect the original developer's gin! This is due to the very natural variances of the oil/flavoring concentrations in natural herbs and spices. Luckily there is a much easier technique to guide you towards getting your gin "just right".
3.1. This technique is best explained and demonstrated with a practical workshop (consider doing the gin making workshop)
4. Selecting the right manufacturing processes to achieve your gin. Not all manufacturing processes are equal. The following diagram summarizes some decisions you will have to make, or can consider when making your particular required style of gin. Looking at the various combinations which you may choose, there are exactly 128 different ways of making your gin...and that does not include your selection of specific hearbs and spices!