Power BI: Preparatory Steps for Creating a Power BI Report

When creating a Power BI report consider the following steps when starting the actual work. The first five steps can be saved to a "template" that can be reused as starting point for each report.

Step 0: Check Power BI Desktop's version

Check whether you have the latest version, otherwise you can download it from the Microsoft website.
Given that most of the documentation, books and other resources are in English, it might be a good idea to install the English version.

Step 1: Enable the recommended options

File >> Options and settings >> Options >> Global >> Data Load:
.>> Time intelligence >> Auto date/time for new files >> (uncheck)
.>> Regional settings >> Application language >> set to English (United States)
.>> Regional settings >> Model language >> set to English (United States)

You can consider upon case also the following options (e.g. when the relationships are more complex than the feature can handle):
File >> Options and settings >> Options >> Current >> Data load:
.>> Relationship >> Import relationships from data sources on first load >> (uncheck)
.>> Relationship >> Autodetect new relationships after data is loaded >> (uncheck)

Step 2: Enable the options needed by the report

For example, you can enable visual calculations:
File >> Options and settings >> Options >> Preview features >> Visual calculations >> (check)

Comment:
Given that not all preview features are stable enough, instead of activating several features at once, it might be a good idea to do it individually and test first whether they work as expected. 

Step 3: Add a table for managing the measures

Add a new table (e.g. "dummy" with one column "OK"):

Results = ROW("dummy", "OK")

Add a dummy measure that could be deleted later when there's at least one other measure:
Test = ""

Hide the "OK" column and with this the table is moved to the top. The measures can be further organized within folders for easier maintenance. 

Step 4: Add the Calendar if time analysis is needed

Add a new table (e.g. "Calendar" with a "Date" column):

Calendar = Calendar(Date(Year(Today()-3*365),1,1),Date(Year(Today()+1*365),12,31))

Add the columns:

Year = Year('Calendar'[Date])
YearQuarter = 'Calendar'[Year] & "-Q" & 'Calendar'[Quarter]
Quarter = Quarter('Calendar'[Date])
QuarterName = "Q" & Quarter('Calendar'[Date])
Month = Month('Calendar'[Date])
MonthName = FORMAT('Calendar'[Date], "mmm")

Even if errors appear (as the columns aren't listed in the order of their dependencies), create first all the columns. Format the Date in a standard format (e.g. dd-mmm-yy) including for Date/Time for which the Time is not needed.

To get the values in the visual sorted by the MonthName:
Table view >> (select MonthName) >> Column tools >> Sort by column >> (select Month)

To get the values in the visual sorted by the QuarterName:
Table view >> (select QuarterName) >> Column tools >> Sort by column >> (select Quarter)

With these changes the filter could look like this:

Step 5: Add the corporate/personal theme

Consider using a corporate/personal theme at this stage. Without this the volume of work that needs to be done later can increase considerably. 

There are also themes generators, e.g. see powerbitips.com, a tool that simplifies the process of creating complex theme files. The tool is free however, users can save their theme files via a subscription service.

Set canvas settings (e.g. 1080 x 1920 pixels).

Step 6: Get the data

Consider the appropriate connectors for getting the data into the report. 

Step 7: Set/Validate the relationships

Check whether the relationships between tables set by default are correct, respectively set the relationships accordingly.

Step 8: Optimize the data model

Look for ways to optimize the data model.

Step 9: Apply the formatting

Format numeric values to represent their precision accordingly.
Format the dates in a standard format (e.g. "dd-mmm-yy") including for Date/Time for which the Time is not needed.

The formatting needs to be considered for the fields, measures and metrics added later as well. 

Step 10: Define the filters

Identify the filters that will be used more likely in pages and use the Sync slicers to synchronize the filters between pages, when appropriate:
View >> Sync slicers >> (select Page name) >> (check Synch) >> (check Visible)

Step 11: Add the visuals

At least for report's validation, consider using a visual that holds the detail data as represented in the other visuals on the page. Besides the fact that it allows users to validate the report, it also provides transparence, which facilitates report's adoption.