math facts

As I have spent countless hours researching strategies in how to improve fluency of basic facts with my students, I am still confused. There are some strategies out there that seem to work but a lot of what I read continually shows that students who spend time engaged in  "meaningful practice" will lead to more fluency with these facts.
If meaningful practice will lead to improvement, I wonder if daily flash cards or subitizing drills will improve my students skills with basic facts. Many articles mention that a solid understanding of number sense is key. Many educators have not heard of number sense and there seems to be no two definitions that are the same. Number sense is the awareness of number names, values, and relationships. One researcher even suggested that number sense is critical in computational fluency as the importance of phonemic awareness is in reading. Is there a link to number sense and fluency?
Number sense can be achieved through a variety of experiences; use of manipulatives, discussions, various strategies, and other activities that help students better see patterns, connections, and relationships to numbers. The ability to subitize is also a key element of number sense. Subitizing is the ability to instantly see how many and requires one to just know instead of using counting. Subitizing requires children to visualize  mental images in their minds.
I am curious as to whether flash cards and daily subitizing activities will lead to more rapid recall of basic facts. Right now, my students seem to lack the ability to recall basic facts with little or no hesitation. What can I do to help them to become quicker in solving those problems.