As an elementary math support teacher (helps kids who struggle in grades K-4), I love that you are asking this question! I couldn't agree more with all of the posts, especially the one about keeping it fun and natural and not forced.
Number formation - lots of ideas already (touch, playdough, trace, color)
Number recognition - make cards where you draw the number on it. Have the set around the house and as you play together, count things sometimes and show her the card that matches the items. When you count items, touch each one and move it aside. Better at first if all items are the same.
Quantity recognition - get a set of double six plain dominoes ($5 at Walmart) and play dominoes. You put one down and match the dots to make a long train of dominoes
Estimate - Ask her "about how many matchbox cars are lined up" then actually count...
Read books. There are loads of counting books. You could do a search for preschool math books at the library. A few of my favorites: One Gorilla, Ten Wriggly Wiggly Caterpillars, Telling Time with the Very Busy Spider, etc.
Play board games. Have her count as she moves her pawn. There are math board games, too. Go Diego Go 1,2,3 (animals and numbers 1-10) and LeapFrog's My Card Games (comes with Math Rummy)
Play internet games:
http://www.sproutonline.com/ PBS Sprout – click on Games; Under Type of Games, select Numbers and Counting; select games like Spud’s Counting Game and Connect the Dots
http://funschool.kaboose.com/preschool Many great math games including Connect the Number, Counting on a Cloud, Fishin’ Mission, Monster Numbers, Motor Match, Number Matching, Paintbrush Math, Shape Racer, Stacker, Teach Me 1, 2, 3s
http://www.knowledgeadventure.com Many fun math games…Go to tab “Math” and select “Preschool Games” or “Kindergarten” Games
http://www.mathplayground.com -click Math Games and try “Balance Scales”
http://www.funbrain.com - too hard for preschoolers, but great when in school
Love it! Keep playing and trying things.