Your question is extremely broad so all I can do is give you an extremely broad answer. More specifically, I'll provide you a study done by John Hattie (2008), who meta-analyzed 800(!!) meta-analyses on effective teaching methods, used in primary education among others. 

The linked document shows a "brief" overview of the different methods rated and sorted by their effect sizes. 

Hattie has also written much about providing feedback and how that affects students' learning ability (e.g. Hattie, 2007)

[Hattie, J., & Timperley, H. (2007). The power of feedback. Review of educational research, 77(1), 81-112.][2] 

 [Hattie, J. (2008). Visible learning: A synthesis of over 800 meta-analyses relating to achievement. Routledge.][1]


  [1]: https://pdfs.semanticscholar.org/2392/2d3e21a8c447bf95c18dacf630e6ce45eea3.pdf

  [2]: https://www.bvekennis.nl/Bibliotheek/16-0955.pdf