How to properly declare variables in a Unity component?

VariablesInUnityMonoBehaviour.cs

using System;
using UnityEngine;

namespace awesomeCompanyName.awesomeProductName.relevantNaming
{
    public class MyComponent : MonoBehaviour
    {
        private OtherComponent _usedOnlyByMe;

        [SerializeField]
        [Tooltip("Explicit description of what I am.")]
        private OtherComponent _setInInspectorAndUsedOnlyByMe;

        /// <summary>
        /// Explicit description of what I am.
        /// </summary>
        public OtherComponent ReadOnlyByOthers => _setInInspectorAndUsedOnlyByMe;

        /// <summary>
        /// Explicit description of what I am.
        /// </summary>
        public OtherComponent ReadWriteByOthers
        {
            get { return _setInInspectorAndUsedOnlyByMe; }
            set { _setInInspectorAndUsedOnlyByMe = value; }
        }

        public OtherComponent DontDoThis; // Never!

        private void Awake()
        {
            // Check required fields.
            if (!_setInInspectorAndUsedOnlyByMe)
                throw new InvalidOperationException("Explicit message about what is missing.");
        }
    }
}