Accept the fact that death has come. Don't try to ignore it. Don't try to evade it. And don't pretend that it hasn't happened. It is good to live the past creatively, but don't do it in the sense that you do not allow yourself the truth of the matter that a loved one has died.
God's Word has always stood the test and has helped so many people. The reason for this is that it is God's Word. God, among many things, is a helper. He has recorded through His prophets and messengers words that can be of comfort. So use your Bible. Saturate yourself with the Scriptures. Some people feel that reading a verse or two is not as helpful as reading a longer section. That may be true. For example, when you have an infection you must get an antibiotic into your bloodstream. You must continue taking the medication not just for a day or two, but for an extended period. And so, God's antibiotic for the illness of sorrow is a large dose of His Word taken frequently.
This is a necessity, the greatest antidote for one who is grieving and who wants guidance and direction. Such a person can't go wrong by talking to God, communing with Him, and praying to Him. Talk to Him as you would talk to another person because He is concerned about you.
We need to vent our emotion. Crying is one way we can do this. I have known people who have never cried and one in particular became very ill because of this. Express your emotions, express your grief. Cry. Jesus cried. When we cry we relieve inner tensions and they do not build up to explode with shattering force later.
Help someone else. Helping others is one way to overcome a situation within yourself. You will become a blessing to others and you will be helping yourself. You will pull yourself out of the confines of your own situation. My advice would be: INVOLVE YOURSELF! It is very wrong for people to think of their loved one as dead when he passes on.
Furthermore, it is wrong to envision the loved one in a casket, for he is not there; only the body in which he has lived for x number of years is there. We should rather think about that loved one as we knew him, up and about his business. When a person dies, "the real person" goes to be with God and the old body is left behind.