Perspective on the future is important because it determines how motivated and willing people are likely to be to pursue self-help projects, and to stick with those self-help projects when the going gets rough and effort is required. Perspective on the future determines how committed to a project a person is likely to be, and commitment tends to predict success.
People's ability to become motivated and committed to a project is linked to how optimistic or pessimistic they are (e.g., how easy or difficult it is for them to believe that good things will happen to them), and by their degree of self-efficacy (which describes how willing they are to believe that they can accomplish things they want to accomplish). Optimists are hopeful people; if they see a glass with some water in it, they tend to describe it as being 'half full'. In contrast, pessimists tend to believe that more bad things are likely to happen than good; they will see the glass as 'half empty' so as to emphasize the negative. Optimism vs. pessimism and self-efficacy are related ideas; people who are optimistic tend to also believe that their efforts to better themselves will have some positive effect on their lives. In contrast, pessimistic people tend to see themselves as less effective. Self-esteem, which describes how good a person feels about themselves, is a related idea. Optimistic people who believe that they can change their lives tend to feel pretty good about themselves and their chances of success, while pessimistic people who feel more helpless to influence events tend to feel less positively inclined.
There is no real magic to making a self-help project successful. What is necessary is that you believe that change is possible, that you create a good plan for change and then that you execute that plan, doing what is necessary to bring it to completion. Together, motivation and commitment are the fuel that makes this process possible. Without motivation, you might not get started on a self-help project at all. Without commitment (which is nothing more than sustained motivation) you might abandon your self-help project in mid-stream. When motivation and commitment are adequate, people find the strength to continue forward until their projects are completed.
Motivation is linked to optimism. If you tend to be optimistic about your life, you are more likely to start self-help projects and then to follow them through to successful outcomes than if you are pessimistic For this reason, it is to your benefit that you work to become as optimistic as you can legitimately become.
Challenging your pessimistic style essentially reduces to an exercise in changing thoughts. Think of pessimism as a variety of cognitive bias that you unconsciously apply to your appraisals of events and you'll have the idea. When you are pessimistic, you are biased to interpret events in a negative, and often excessively cautious manner. Your automatic thoughts have a negative tone. You can become more aware of this negative bias by practicing cognitive restructuring exercises (link to discussion of Cognitive Restructuring contained in this document) designed to identify the bias in your negative automatic thoughts and challenge them with more objective observations.
The other methods we've reviewed for changing thoughts can be helpful to you here as well. You can use self-suggestion methods to help teach yourself the habit of being more positive. Identify a set of positive affirmations that you can legitimately buy into and then repeat them to yourself again and again in a systematic manner, perhaps while practicing relaxation exercises, autogenic training or self-hypnosis.
You can use the thought stopping technique to help interrupt chains of negative thoughts as you realize they are happening, and then either distract yourself from them (so as to interrupt their further execution), or challenge them with those positive affirmations you've previously developed
If cognitive restructuring is too formal for you, you can practice a more informal version of it by simply keeping a daily journal and writing down your reactions to events and your expectations. As you read over older entries, you will become sensitized to the ways that you habitually interpret events in a dim, negative and overly cautious light. Over time, you will become more adept at realizing that you're doing this in the moment these thoughts and interpretations occur, and will have more and more chances to interrupt and challenge those biased interpretations.