See pronunciation tips on the target sound here

Practice saying the words with the target sound: 

big, bills, bit, brick, bridge, brisk, build, chill, chin, chip, did, dip, 

dish, disk, drill, drink, drip, fifth, fig, fill, film, fish, fist, fit, fix, flip,

gift, give, grim, grin, grip, guilt, hill, him, hip, his, hit, if, ill, in, inch,

 is, it, kid, kill, kiss, lick, lid, lift, limb, lint, list, live, milk, miss, mist, 

pick, pin, pit, pitch, prince, print, quick, quit, ribs, rich, rid, rip, risk, 

script, ship, sin, since, six, skill, skin, slid, slim, split, spill, stick, stiff, 

still, strict, thick, thin, this, till, tin, tip, trim, trip, which, win, wish, 

wit, with.

To improve your saying the target sound practice saying the word with the sound for several times:

e.g.: this is this is

       is this is this is this

       ***

      big ridge 

      big dish

      big gift

      big hit