This is a very simple trick that all the celebrity make up artists have been using for ages:
Dip the brush into the mascara as usual, then clean it on a tissue. That's right, just swap it into a paper tissue to remove the excess of the mascara and they apply as usual. Allow a few seconds to dry and then repeat the procedure: this way you won't get the lumps on your lashes and the two layers of mascara will make your eyelashes fuller and bigger.
Don't worry about wasting the product on the tissue, you would have the clogged excess on the top of the mascara tube anyway and plus, mascaras have a very short expiration date (about 6 months).