How you can calculate the sales target after deciding the best method you can use?

that's depending on the company situation and concepts were used

You can take many points in your way  to calculate the sales target :

1- financial situation of the company ( bank + cash )

2- stock inventory

3- term of the operation.

4- market study

and many others points can be dicussed deeply.

whenever i have all the reiqured inf, such as sales history per outlet , top items availability, staffing plan and others , then by based on company growth plan and market movement i can decide the target and incentive  

First , I have to look deep at the business current situation by determining the factors that can affect my business growth, revenue quarter  by quarter

Secondly ihave to set the target by unit or representative ,After that it is a mst to have some type of feed back from my unit regarding the target realistically .After that i had to implement a re forecasting process whenever needed based on the progress and other factors