Know it. Memorize it.

Plaindrome

/// <summary>
/// Determines whether the string is a palindrome.
/// </summary>
public static bool IsPalindrome(string value) {
    int min = 0;
    int max = value.Length - 1;
    while (true) {
        if (min > max) {
            return true;
        }
        char a = value[min];
        char b = value[max];
        if (char.ToLower(a) != char.ToLower(b)) {
            return false;
        }
        min++;
        max--;
    }
}