Halachacly, no fasting is allowed on Rosh Chodesh or 15th of Shvat (אורח חיים סימן תקע"ב)
Nevertheless our Guard is right about the whole concept of fasting.
Our rabbis have altered the way we atone for our wrongdoings
Preferably B’Simcha then B’Taanis
To skip breakfast or coffee in these days, decline your productivity, which is on the expense of your profession especially if you are a learner.

However we still have to break the Chomer to adjust our habits
We can achieve this by selecting one of the following methods:

1) Taanis Shoois :
Not to eat for the [any time limit] from when you get home
Not to eat anything from 6 to 8 in the evening

2) Taanis Haravid:
a) Put your utensil down between each bite
b) Don’t eat food in the method you enjoy it most (Like colder or warmer temperatures, or separate from the foods you like mixed etc.)

3) Taanis Dibur:
Not to speak “in any way” for a “period of time”.
Or, “a specific topic” for instance “Gaza war” for a day.
Or, to a specific individual, which whom you enjoy to schmooze with.

4) much more, you can envision them yourself

Warning: a Kabala ought to be personalized and small
Personalized subtract the routine from the thrust, divided by your aptitude, added to the main goal
Small even minute ones are usually tough enough since the kabala itself toughens the plight tenfold or more

1) Taanis Shoois :
Not to eat for the [any time limit] from when you get home
Not to eat anything from 6 to 8 in the evening

3) Taanis Dibur:
Not to speak “in any way” for a “period of time”.
Or, “a specific topic” for instance “Gaza war” for a day