I find code consistency really important. This removes a lot of mental burden from the developer.
One of the conventions that is quite common in C#is to use camelCase for local variables and _camelCase for private or internal fields.
An example:
Unfortunately this convention is not automatically enforced by Visual Studio. To fix this you can add an editorconfig file with the following rules:
dotnet_naming_rule.instance_fields_should_be_camel_case.severity = suggestion
dotnet_naming_rule.instance_fields_should_be_camel_case.symbols = instance_fields
dotnet_naming_rule.instance_fields_should_be_camel_case.style = instance_field_style
dotnet_naming_symbols.instance_fields.applicable_kinds = field
dotnet_naming_style.instance_field_style.capitalization = camel_case
dotnet_naming_style.instance_field_style.required_prefix = _