Repeating the word(s) over and over, writing them and listening to them.
If it's a specific sentence, you can record yourself saying it and repeat it.
As for learning Spanish in general, try doing all those things I said before AND listening to movies in Spanish with subtitles.
Good luck!
1) dos, quatro
2) diez, veinte
3) seis, doce
4) doce, dieciseis
5) diecisiete, diecinueve
6) seis, diez
7) ocho, diez
8) trece,quince
