Contemplation
When you begin meditation, you will be plagued with thoughts from your surface mind, which acts like a huge Memo pad. It carries messages, reminders, pressing thoughts, problems to solve, unresolved issues etc. It is constantly busy, it NEVER rests, thoughts, thoughts, thoughts, one after the other, all clamouring for attention.
Before you attempt to clear your mind, with the breath awareness exercise below, it is wise to deal with these surface thoughts by the act of contemplating them. Sit comfortably, do the relaxation exercise and think, nothing more, just think. Search out the strongest thoughts in your mind and examine them, try to resolve and understand them.
Note the word: THINKING. Contemplation does not involve clearing the mind, or visualisation. It requires you to THINK, deeply and thoroughly, about something, to gain a deeper understanding of its nature and how it relates to you, an insight.