Lonely people often feel that conflicts or problems in a relationship mean that the relationship has 'failed' in some way. This is not necessarily true. Lonely people tend to blame both themselves and others for their unhappiness. Recognise that some relationships just 'do not work out' and no one is to blame. Try to understand other people and consider their feelings.
Lonely people are often self-centred and think only of themselves.
This leads to being easily injured or gaining an inflated opinion of yourself. Practice tasks to reduce your loneliness. Try to meet and talk with one new person each week.