Most Polish speakers do the following things when they speak English:

1.  Confuse E and IH (say sight or sit)

2.  Say EH instead of AH (say bet instead of bat)

3.  Say EW instead of OOH (say Luke instead of look)

4.  Say O instead of OW (say no instead of now)

5.  Say UH instead of ER (say but instead of Bert)

To address these mistakes practice the following sounds:

E, IH, AH, OOH, OW, ER