To begin with, put yourself in the presence of the Lord. By this, I mean that you draw your attention to some way that you have related to the Lord in the past or in some way that inspires you in the present. This can be an experience, an image of sacred art, a movie, or anything that you associate with God, Father, Son, and Holy Spirit. It might be helpful in the beginning to relate to the Son, Jesus Christ, because this relationship is the most tangible. The key is that it is something that resonates with you.
Having drawn your attention on the Lord, now pay attention for a moment to your body and your interior dialogue. Look at what you are experiencing. Are you particularly tense in any area? Is there pain or discomfort? Is there some image or idea that you keep coming back to? In this beginning step, just pay attention to where you are at. As you notice different things, relate them to the Lord. Talk to him about what you are experiencing, and imagine what he might tell you.
Feel free to stay at this part of the meditation. If you feel particularly relaxed and feel called to move on, do so. However, recognize that the meditation can stay with this beginning step and be fruitful.
If you feel called to, perhaps now you can bring scripture into the meditation. For these instructions, I will discuss imaginative meditation. There are also other ways of doing this meditation.
Take a passage that resonates with you. Start by reading the passage. Try to imagine the context. Look at the details surrounding the scene. Who is present, what are they wearing, what are the smells, etc. These details are important. You can also use your imagination to include other details. For example, does someone you love or struggle with suddenly appear in the scene? If so, integrate them into your meditation. Let your creativity build the meditation.
Prayerfully read the passage and pay attention to things that surface. Ask yourself, does a particular emotion arise? Does a memory from the past seem to surface? As you meditate on the passage, more and more things will open up. Learn to be receptive to whatever may come. Also, throughout this meditation, you should be relating everything to the Lord because he is present. This is not a strict rule (i.e. don’t feel like you are not meditating if some talking is not directed towards God). The idea is that all of this is done within the context of a relationship with God (Father, Son, and Holy Spirit). Share with God whatever you are experiencing.
As you relate things to the Lord, imagine what he might say to you in response. Let your intuition guide you to discover and connect your meditation to things you have read or heard. The Spirit often speaks to us in the associations we make in our interior dialogue.
Finally, realize that your prayer does not have to be all doing. As you walk through the passage, let yourself come to the place where you simply rest with something that has surfaced. Do not be afraid that your meditation will lead you to a place in which you are doing nothing. Prayer is not about activity but rather is a dynamic of love which involves a variety of moments. Some of those moments include simply resting with the Lord.
I hope this proves helpful.