Before treating each of these six, however, it is necessary to establish some context: specifically, to review some aspects of the basic Buddhist teaching of karma. To fulfill or complete something means to do something; to practice a paramita means to be active about it, to act on it. Karma means action. Things in the world arise due to causes and conditions; they persist due to causes and conditions, and change over time; they fade away, decay, over time due to causes and conditions. And these causes interact with each other in particular ways (this is called "dependent origination," of which more later).
Generally in human life, actions follow intentions. If my intentions are out of control, my actions are too. If I wish to make some changes in the pattern of my activities, then I need to work with my intentions, and in particular I need to firm up that intention to make a change in order first to break the old pattern and establish a new way to work in its place. Buddhists make vows to accomplish this. The "Verse of the Kesa" is one example: a contemplation intended to deepen one's commitment to practice.
Similarly, vows also serve to bring people together around their good intentions, to make a community of good intentions (which is to say, to build a durable sangha). By the logic of dependent origination, making vows together makes a kind of continuity on positive terms that will bear particular fruits in future activity, like tying many life-rafts together in a seastorm for security in numbers. This is another reason why it helps to practice with others who are seeking to fulfill or complete in themselves the same aspirations you seek to perfect.
Consider, for instance, an item from the morning service we use at the Tendai Buddhist Institute. This is called "Shichi Butsu Tsukaige," and it is beautiful:
Wishing together with all sentient beings:
Do not commit evil,
Do everything that is good,
Purify the mind.
This is the teaching of all the Buddhas.
I bow to the sacred clouds.
At the very beginning is a vow made here, a together-vow if you will (and this part of the service is recited by everyone present, with conviction). Also conspicuous is the offering at the end, which speaks directly to the first paramita, which is dana or generosity.
To make this a bit more concrete, it helps to think of the example of learning a new skill or breaking an old habit (both amount to the same thing on principle). You see the harmful consequences of keeping this habit, and you see why it would be better for everyone if you just cut it out and used your time and energy in another way, but the force of that habit keeps you in the same cycle again and again. This is an object lesson in karma for you. How do you break into that? You have to start with the intention to quit smoking cigarettes or to cut back eating so much sugar or whatever it is. You need to identify the causes and conditions that keep you doing this, and work with those (and this may mean seeking out specific resources to help, or removing yourself from situations that will guarantee the failure of your intention). As you can imagine, the logic of karma involves a logic of connection and interconnection; a simple vow sweeps up into itself a very involved web of consequences. You make a vow to stop smoking. You work at it, you try, and you fail. You renew your vow. You try again with more energy and adjusted tactics. You fail. You learn from that and, again, renew your vow, give it everything you have, last a bit longer and build more confidence before failing a gain. And then you do it again, and again, and again until you finally get it right or you die trying (or, more likely, die not trying very hard).
Buddhist practice amounts to learning how to stop doing the stupid and start doing the useful, just like quitting smoking or learning how to ride a motorcycle or make a decent batch of chilaquiles. The principle is the same but the methodology is much, much more comprehensive. The paramitas are a way to keep that methodology clear in one's mind.
As a practical matter, I find it helpful to reflect on intentions in the morning, in particular to review the kinds of commitments (samaya) I have made in the past, with an eye toward keeping to those with energy and spirit. And in the evening, a frank and honest assessment of the day's events and my own actions of body, speech, and mind offers a fine window into the condition of my own condition as it were. This is how learning can happen in an everyday way.
Remember that meaningful commitments are difficult to keep. Help is available; no one's case is hopeless or lost. There are Buddhist methods to help people deal with their own shortcomings and to strengthen their sense of purpose. Notice how even repentance verses the intention of getting the bodhisattva's work done (this is the General Repentence Verse, also from the Tendai morning service):
For the sake of all the sentient beings in the Dharma realm, let me cut off my three attachments and repent my transgressions by invoking the Buddhas and Bodhisattvas, and by praying for all sentient beings.
Counterproductive action can be counteracted by the right kind of productive action, properly applied. That is the logic behind this methodology.