1) Use Pascal casing for type and method names and constants:
public class YourClass
{
const int ConstantVariable = 100;
public YourMethod( )
{}
}

2) Use camel casing for local variable names and method arguments. Use p prefix for parameterized vairables:
int intNumber;
void MyMethod(int pintNumber)
{}

3) Prefix interface names with I:
interface IMyInterface
{..}

4) Prefix private member variables with m.

5) Suffix custom attribute classes with Attribute.

6) Suffix custom exception classes with Exception.

7) Methods with return values should have names describing the values returned, such as GetObjectState( ).

Use descriptive variable names.
1. Avoid single-character variable names, such as i or t. Use index or temp instead.
2. Avoid using Hungarian notation for public or protected members.
3. Avoid abbreviating words (such as num instead of number).
9)Always use C# predefined types, rather than the aliases in the System namespace. For example:

object NOT Object
string NOT String
int NOT Int32

10) With generics, use capital letters for types.
//Correct:
public class LinkedList
{…}
//Avoid:
public class LinkedList
{…}

11) Use meaningful namespace names, such as the product name or the company name or can use related module name.

12) Avoid putting a using statement inside a namespace.

13) Group all framework namespaces together and put custom or third-party namespaces underneath:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using MyCompany;
using MyControls;

14) Maintain strict indentation. Do not use tabs or nonstandard indentation, such as one space. Recommended values are three or four spaces.

15) Indent comments at the same level of indentation as the code that you are documenting.

16) All comments should pass spellchecking.

17) All member variables should be declared at the top, with one line separating them from the properties or methods:

public class MyClass
{
int mintNumber;
string mintName;
public void SomeMethod1( )
{}
public void SomeMethod2( )
{}
}

18) A filename should reflect the class it contains.

19) Always place an open curly brace ({) in a new line.