Heya! This is just a brief introduction to PA techniques. It works on the premise that with everything we say, we put a truth into the universe. For example, if we say "I am fat", whatever weight we are, we will become fat. Opposingly, if we say, "I am successful", that goes as a truth into the universe and it becomes true in our life.
Another way of looking at this is in the view of programming our sub-conscious. Our sub-conscious kinda 'believes' everything we say, and trusts that we are speaking the truth. Then it manifests that truth.
So, to practice PA we must realise that we can take control of what we are programming the universe/our sub-conscious, with. Negative thinking patterns can build up by phrases like "I am always depressed" or "I can't do..." or "I am stupid". These are like mini spells that we do all the time. We thoughtlessly curse ourselves! :P
We can change this deliberately by replacing our negative instruction with positive instruction to our selves. Eg: "I am happy", "I can do whatever I choose to do" "I have a capable mind".
For example, I was having a problem where I kept going back to sleep when I woke up in the morning. So, I affirmed "When I wake up I get out of bed". It worked within two days. Once I had made my coffee, I went straight back to bed though, lol, I hadn't quite thought it through! So, I added another affirmation of "when I'm awake I'm active". xD
To start, pick your affirmation, and just say it with no doubt, out loud, ten times a day. Always keep your affirmation in the present tense, this is very important. Also, always make it a positive statement (ie: don't use words like 'not, don't, etc) You can go a long way with affirmation and make it part of your lifestyle.
Some examples of positive affirmtions:
I heal easily
I am loving, lovable and loved
I trust in life
I deserve to be happy
To summarise, - you are already doing this! What you can aim for, is to take control of it! :D