That depends on how you define “resistance.” Usually, when I mention “resistance” in the context of Law of Attraction/manifestation, it’s a synonym for “Tests from the Universe.” 

Resistance—i.e., a virtual brick wall suddenly popping up that keeps you from manifesting your heart’s desire—usually happens when you’re trying to manifest something big and truly life-changing.

I recently wrote a post about it that explains quite well how resistance works and how to overcome it. 
However, if you mean “resistance” as in your own reluctance to manifest or the mixed messages you’re sending, then the answer is, you need to work on aligning your thoughts, feelings, words, and action.

As long as you contradict yourself—for example, by trying to manifest money but constantly saying, “I can’t afford this,” or “I’m broke,” or by thinking about your lack of money when visualizing—it just won’t work right.

You need to believe that the abundance you’re looking for is out there and available to you. All you’re waiting for is its manifestation in the 3D world.

One thing that helps when trying to manifest money, I found, is giving. If you’re a Christian, you may want to consider tithing—that means, giving one-tenth of your income to your church. If you’re not a Christian, give one-tenth to a charitable cause of your choice.

One-tenth sounds brutal, and I’ll tell you, it’s not easy to just give away a chunk of money like that when you’re already struggling to pay your bills.

But there’s magic in this too: You may suddenly find all kinds of unexpected cash arriving at your doorstep. The (financial) blessings you send out literally circle around and flow back to you.

That, by the way, also goes for non-material blessings—and the curses—you send out. (Find out how to send blessings to yourself and others with my free report, The Goodwill Manifestation.) 
​
Ultimately, you’ll realize that your outer reality is a reflection of your inner reality.

That’s not what I would call “manifestation,” that’s black magic. Which, needless to say, nobody should ever engage in.

I believe that causing other people harm will ultimately come back to haunt you and destroy your soul (aka, put you squarely into the territory of the “Dark Side”).

Even if you “only” wish something terrible to happen to someone (vs. actively doing something to harm a person), it’s an act of evil. Leave the punishment for bad deeds up to God… and trust that evildoers will get their just desserts sooner or later.

Of course, if you’re a Christian, you should go even further and try to forgive that person who did something bad to you. Forgiveness is really mostly for your own sake, not for the other person’s, and it can do wonders for you in terms of stress relief and peace of mind.
​
Try the Goodwill Manifestation to spread blessings to everyone you meet… even to unpleasant people. It’s a very simple technique, and you’ll see amazing things happen.