Loving yourself takes two things, love and a self. Love is the easy part. If your self is difficult to love then you start with loving things that are not you. Think of people and things that you love. Think of times and places that you love, think of foods and activities that you love. If you can think of even one thing that you love and focus intently on that one thing and how it makes you feel then you can fill yourself with love. When you fill yourself with love, you have effectively loved yourself, but that is not enough.
To love yourself you have to imagine that you are lovable. To demonstrate that you are lovable, think of some thing or somebody that has loved you. Everybody has grown up with some love in their life. Without love we wither away and die. When you think of a person or pet who loves you, think about what that love is and how that love feels. Breathe in and out with how others love you. Once again you are filled with love, and you have loved yourself, but that is also not enough.
Understanding that you love and are loved and being able to fill yourself with love will help you connect with the love in your life. To focus that love on yourself, you take a good look at yourself. If you are not feeling lovable, then you are suffering. look into your suffering and see how much you would like that suffering to stop. That feeling of wanting suffering to stop is compassion. When you feel compassion for yourself you are loving yourself. You feel clearly that you are deserving of love and peace and freedom from suffering. When you feel compassion for yourself you have loved yourself, but that is not enough.
Once you have demonstrated to yourself that you can love yourself, then you must practice loving yourself all the time. Pay attention to your thoughts and feelings about yourself. Recognize when you are thinking bad things about yourself and see that when you think those things you are suffering. Conversely, if you notice you are suffering, see if you are thinking bad things about yourself. Then clear your mind, fill yourself with love and compassion and start again. You may do this 10 or 10,000 times, but it is still not enough.
When you practice loving others, being loved by others, and loving yourself, and you realize that what and where you are is enough, that is enough. Then, keep practicing.