I’d recommend having a notebook in which you’d write down the time you spend practicing every day. 
By taking note of a certain regular activity, you will be aware of whether or not you’ve done what you wanted to do that day. If you don’t practice on a certain day – still list that day’s date and fill in a big ZERO next to it. 
Doing so is, to be sure, frustrating, but that’s the effect you want: if you get somewhat frustrated because you were lazy that day, it’s all the more likely that I will not be lazy the next day!
When I do practice, I write down how long I did so.
For example, if I practice an hour in the morning, and another hour and five minutes in the afternoon, I’ll note:
„60 + 65 = 125 minutes”. (I like to be precise).
Your daily list will make sure you never skip a day – and if you do, looking at that blank entry in your list on the following day will motivate you to learn six new words instead of three, to make up for lost time.
Your list could be as simple as this:
Jul 1 X
Jul 2 X
Jul 3 X… etc.,
with each „X” meaning that you learned your three words for the day.
Are you determined to start towards your goal of boosting your vocabulary? Then go get a
notebook now, or if you don’t have one at hand, a piece of paper will do (you can always copy the first few days’ results into the notebook when you get one). The idea is to start now, lest you simply decide to „put it off” till another day… all-too often, that „other day” never arrives, and we haven’t progressed at all!