I especially loved teaching second grade. There were tricks I used to make my students very adept in math. To teach multiplication you will need a package of half-inch grid paper. If your school doesn't carry it, DO NOT BUY IT.
(Make a list of materials you know you will use and put each item on a post -it note with a Sharpie. Then, put each post-it note on your classroom easel. During Open House, Tell your parents you would be delighted if they would each take a note and purchase that supply for your classroom. You will be surprised at the wonderful items you can get. Don't forget a thank you note.)
Instead, make half -inch squares on a piece of paper and copy as needed. You will probably never need more than four papers per pupil. Pass out one piece of paper to each student. Have them put their first and last names on the top line, one letter in each square. Then skip a line. On the third line, write the numbers 1-12, with one number in each square. On the next line, have students skip count by two's. They will begin at 2 and end at 24. As the students are working, you model the skip counting on the white board. Can you guess what comes next? You will model skip counting by 3's, putting one number in each box. Be careful when you are modeling. Many students will need to copy from you and you must not go too quickly. As long as they understand the concept they will do well. You may want to let them work in groups because they will think it's fun and will be more apt to pay attention. I would stop this activity before 30 minutes at the most. (As a rule of thumb, I try to stop activities while student's are still having fun because they will look forward to it the next time.)
On another day, pass out a grid paper again. Give the direction to write their name at the top and write the numbers 1-12 after they have skipped a line. Practice skip counting orally until you get to 5's. Then model the numbers on your white board. As students get better and understand the concept you may have them work independently. Some will get skip counting by 12's very quickly.
Next, when students have completed an assignment on regular paper and there is still time left, have them turn their paper over and write 1-12 at the top. They will need to leave spaces or the numbers won't fit. Also, when you are waiting in the hall with your class, in a lowered voice, have them practice skip counting. When I had bus duty, I tried to get the bus lines to skip count. Students can get excellent at this quite quickly. When they get really good at skip counting, you can have them practice skip counting backward orally. Ask the class who can skip count backwards by 7's beginning at 25? If you carry this out, students will be in a stronger position the next year. Happy Counting!