Barry Schwartz wrote one of the most influential books on the art, no, science of maing choices. Read this alongwith the guide to Nudge.

Highlights:

When given free samples of jams in a store, 30% of people exposed to 6 jams bought a jar. Only 3% of people exposed to 24 jams bought a jar. A large array of options discourages customers because it forces an increase in the effort that goes into making a decision. So consumers decide not to decide.
Thinking about the attractions of some of the unchosen options detracts from the pleasure derived from the chosen one. Faced with many options or decisions in your life? This will change the way you look at them. We feel worse when we have too many options.

The main arguments of the book:
1. We would be better off if we embraced certain voluntary constraints on our freedom of choice, instead of rebelling against them.
2. We would be better off seeking what is "good enough" instead of seeking the best.
3. We would be better off if we lowered our expectations about the results of decisions.
4. We would be better off if the decisions we made were non-reversible.
5. We would be better off if we paid less attention to what others around us were doing.

Most good decisions involve these steps:
1. Figure out your goals
2. Evaluate the importance of each goal
3. Array the options
4. Evaluate how likely each of the options is to meet your goals
5. Pick the winning option
6. Later, use the consequences of your choice to modify your goals, the importance you assign them, and the way you evaluate future possibilities.

As the number of options increases, the effort required to make a good decision escalates as well.

Following rules eliminates troublesome choices in your daily life:
Friendships often sustain themselves on a combination of standards and routines. We're drawn to people who meet our standards and then we stick with them. We don't make a choice, every day, about whether to maintain the friendship. We just do.
Some cultures have constraints in oppresive abundance, while ours has eliminated as many constraints as possible. But oppression can exist at either extreme.
Wanting and liking are served by fundamentally different brain systems.
The downside of abundant choice is that each new option adds to the list of trade-offs.
The quality of any given option can not be assessed in isolation from its alternatives. One of the costs of any option involves passing up the opportunities that a different option would have afforded.
Excellent advice for managing our own psychological response to choice : Pay attention to what you're giving up in the next-best alternative, but don't waste energy feeling bad about having passed up an option further down the list that you wouldn't have gotten to anyway.
The existence of multiple alternatives makes it easy for us to imagine alternatives that don't exist. When we engage our imaginations in this way, we will be even less satisfied with the alternative we end up choosing.
There is no objective "best" vacation, job, or activity. What matters is the subjective experience.
Being forced to confront trade-offs in making decisions makes people unhappy and indecisive.

Options & Tradeoffs
Difficult trade-offs make it difficult to justify decisions, so decisions are deferred.
Easy trade-offs make it easy to justify decisions.
Single options like somewhere in the middle.
When people are presented with options involving trade-offs that create conflict, all choices begin to look unappealing.
People put a higher value on things (when asked to guess a value) when evaluating in isolation than when evaluating as a part of a group.
When people are asked to give reasons for their preferences, they may struggle to find the words. So they grasp at what they can say, and identify it as the basis for their preference. As time passes, the reasons that people verbalized fade into the background and people are left with their unarticulated preferences. People's satisfaction with the decision they made, fades.
There are pitfalls to deciding after analyzing : as the number of options goes up, the need to provide justifications for decisions also increases.
The more options you have, the more likely you will experience regret.

How to be wise choosers:
If you seek and accept only the best, you are a maximizer.
If you settle for something "good enough", and don't worry about the possibility that there might be something better, you are a sufficer.

To a maximizer, satisficers appear to be willing to settle for mediocre, but a satisficer may be just as discriminating. The difference is that the satisficer is content with the merely excellent as opposed to the absolute best.
The goal of maximizing is a source of great dissatisfaction.

Satisficing is, in fact, the maximizing strategy. The best thing people can do is to satisfice.
- Maximizers savor positive events less than satisficers and do not cope as well with negative events.
- After something bad happens to them, maximizers' sense of well-being takes longer to recover.
- Maximizers tend to brood or ruminate more than sacrificers.

Whereas maximizers might do better objectively than satisficers, they send to do worse subjectively.

1. Choose when to choose.
Decide which choices in our lives really matter and focus our time and energy there, letting other opportunities pass us by. By restricting our options, we will be able to choose less and feel better.

Try this: 1. Review recent decisions you've made, 2. Itemize the steps, time, research, and anxiety that went into it, 3. Remind yourself how it felt to do that work, 4. Ask yourself how much your final decision benefitted from that work.

2. Be a chooser not a picker
Shorten or eliminate deliberations about decisions that are unimportant to you.

If none of the options meet your needs, create better options that do.

3. Satisfice more and Maximize less

4. Limit how much you think about the attractive features of the options you reject.
Unless you're truly dissatisfied, stick with what you always buy. Don't be tempted by "new and improved". Don't scratch unless there's an itch. Don't worry that if you do this, you'll miss out on all the new things the world has to offer.

5. Make your decisions nonreversible.
Agonizing over whether your love is the real thing, or your sexual relationship up to par, wondering whether you could have done better - is a prescription for misery. Knowing you've made a choice that you will not reverse allows you to pour your energy into improving the relationship that you have rather than constantly second-guessing it.

6. Practice gratitude.
7. Regret less
8. Anticipate Adaptation (the fact that the "fun wears off" when you get used to the new choice)
Remember that the high-quality sound system, the luxury car, the big house, won't keep providing the pleasure they give when we first experience them.
Spend less time looking for the "perfect" thing, so that you won't have huge search costs to be amortized against the satisfaction you derive from what you actually choose.

9. Control Expectations
Reduce the number of options you consider. Be a satisficer rather than maximizer. Allow for serendipity.

10. Cut down on Social Comparison

11. Learn to Love Constraints
By deciding to follow a rule, we avoid having to make a deliberate decision again and again.

[From the Great Books  Series. Also see The Success Manual  - Encyclopedia of Advice, which contains summaries of 100+ Most useful books.]