How can mindfulness/awareness be employed effectively for Forgiveness? I don't want to harbor ill-will anymore and I want to forgive others for what they did to me and also forgive myself for my past actions.

So I remain aware and mindful of the thoughts of ill-will that pop up and mindful of corresponding feelings. But this does not seem to alleviate the stream of thoughts and feelings all day. 

How can mindfulness be employed effectively for forgiveness?
I want forgiveness for what others did to me and also forgiveness for myself for my past actions.

The first part isn't in your sphere of control. Having preferences like that other people better forgive you is in and of itself ok, however, if you turn that healthy preference into a command that they SHOULD forgive that will result -as in your case - in anger.
You can however cultivate self-acceptance. You judge your acts as bad but not your personhood. You judge the deed, not the doer, for the doer is fallible and too complex to give a global evaluation.
Just observing ill-will won't necessarily change your underlying beliefs and the resulting perceptions. You need an alternative perception that weakens the old belief. Therefore, mettā is employed to attenuate anger and increase kindness.
Refer to MN 62

&quot;Develop the meditation of good will. For when you are developing the meditation of good will, ill-will will be abandoned.
&quot;Develop the meditation of compassion. For when you are developing the meditation of compassion, cruelty will be abandoned.
&quot;Develop the meditation of appreciation. For when you are developing the meditation of appreciation, resentment will be abandoned.
&quot;Develop the meditation of equanimity. For when you are developing the meditation of equanimity, irritation will be abandoned.

~
You can also try to view people as unique, complex and fallible human beings (like you!), whose mind and body are constantly changing (like yours!),  and that they too are often prey of environmental factors and prior mind/body conditioning (again, like you!) -&gt; At that moment in time these people haven't had better coping skills to regulate their thoughts, feelings and behaviours. In short: &quot;It seemed so to them.&quot;
See them as human beings that have certain aspects that are annoying and then you can take that aspect and wish them metta with regards to the opposite positive quality. So if a person is annoying or dishonest, you can wish them: &quot;May they know the happiness resulting from honesty and friendliness&quot;.
No matter which technique you employ, repetition is key. I employ especially the self accepting technique for over 2 years and it works out. Of course, sometimes I do get angry, but that is to be expected because I too am a fallible human being who can learn from his mistakes and try to restrain himself in the future.