How to play against the Polish opening? 1. b4 It seems like that black can some how equalize. Despite this, I somehow get tricked and lose my games against this opening.
I have played against this opening a lot, sometimes in bullet sometimes in blitz games, and even in casual ones without the clock. some of the opponents were strong candidate masters and sometimes a FIDE master would use it. 

The easiest defense for me is 1...e5 and on 2.Bb2 to simply take on b4. This has several benefits:


White is behind in development ( plays twice with the bishop );
Black hinders White's fight for the center by keeping bishop on a5-e1 diagonal. This is very effective method that simply squelches any initiative White has. He may be equal in the resulting tabya but that is all he gets, and frankly, I believe Black has an easier game;
Black gets half-open e-file which is very useful, since he will play ...d5 and ...Re8 at some point, so he can count on ...d4 push to generate initiative;
Being behind in development and restrained in center, White can't really use b-file;
Since Black has development advantage, the opening of the game benefits him ( ...d4 push mentioned above is useful for this );
All of the Black pieces can acquire best squares ( knights on c6 and f6, bishops on b4 and g4 );
Black has no pawn weaknesses, nor weak pieces, while White has weak pawn at a2;


That is why I would advise you the above approach when battling the Sokolsky attack ( known also as Polish opening or Orangutan ). I have looked into Fritz opening database and found the lines I think give good game for Black in the easiest way ( I have added multiple hoices for Black so you can have a wider choice ). I am going to present them in the below diagram and will explain typical positions and plans afterwards.

[Title "Recommended theory for Sokolsky attack"]
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

1.b4 e5 2.Bb2 ( 2.a3 d5 3.Bb2 ( 3.e3 Nf6 4.Bb2 Bd6 5.Nf3 ( 5.c4 c6 6.Nf3 Qe7 7.Nc3 a6 ) 5...Qe7 6.c4 c6 7.Nc3 a6 ) 3...Bd6 4.e3 ( 4.Nf3 Qe7 5.e3 Nf6 6.c4 c6 7.Nc3 a6 ) ( 4.f4 exf4 5.Bxg7 Qh4+ 6.g3 fxg3 7.Bg2 gxh2+ 8.Kf1 Nf6 9.Nf3 ( 9.Bxh8 Ne4 10.Bxe4 dxe4 ) 9...Qg3 10.Bxf6 ( 10.Bxh8 Bh3 ) 10...Rg8 11.Rxh2 Qg6 12.Be5 Bxe5 13.Nxe5 Qf6+ 14.Kg1 Qxe5 ) 4...Nf6 5.Nf3 ( 5.c4 c6 6.Nf3 Qe7 7.Nc3 a6 ) 5...Qe7 6.c4 c6 7.Nc3 a6 ) ( 2.b5 d5 3.Bb2 Bd6 4.e3 ( 4.Nf3 Qe7 ) ( 4.f4 exf4 5.Bxg7 Qh4+ 6.g3 fxg3 7.Bg2 gxh2+ 8.Kf1 Nf6 9.Nf3 ( 9.Bxh8 Ne4 10.Bxe4 dxe4 ) 9...Qg3 10.Bxf6 ( 10.Bxh8 Bh3 ) 10...Rg8 11.Rxh2 Qg6 12.Be5 Bxe5 13.Nxe5 Qf6+ 14.Kg1 Qxe5 ) 4...Nf6 ) 2...Bxb4 3.Bxe5 Nf6 4.c4 ( 4.c3 Be7 ) ( 4.Nf3 O-O 5.e3 d5 ) 4...O-O 5.Nf3 ( 5.e3 d5 6.cxd5 ( 6.Nf3 c5 7.cxd5 Nxd5 8.Be2 Nc6 9.Bb2 Bf5 ) ( 6.Qb3 c5 7.a3 Ba5 8.cxd5 Nxd5 9.Bc4 Nb6 10.Be2 Nc6 11.Bb2 Be6 ) ( 6.a3 Ba5 7.cxd5 Nxd5 ) 6...Nxd5 7.Nf3 Re8 ( 7...Be7 8.a3 c5 9.Be2 Nc6 10.Bb2 b6 11.O-O Bb7 ) 8.Bb2 ( 8.Be2 Rxe5 9.Nxe5 Qf6 10.f4 Nxe3 11.Qb3 Nxg2+ 12.Kd1 Nxf4 13.Nxf7 Qxf7 14.Bc4 Be6 15.Bxe6 Nxe6 ) 8...Be7 ) 5...Nc6 6. Bb2 d5 7. cxd5 Nxd5 


OK, now you have thorough coverage of your repertoire with Black. I have tried to keep the number of lines to minimum, but all relevant White replies had to be covered. It is time to explain the ideas and plans in each separate position for Black:

[Title "White takes pawn at e5, Black takes pawn on b4"]
[fen "r1bq1rk1/ppp2ppp/2n5/3n4/1b6/5N2/PB1PPPPP/RN1QKB1R w KQ - 0 8"]


In the above position Black has no weak pieces, he is not cramped and has development advantage. White on the other hand does have central pawn majority but he can't utilize it to gain initiative. The best he can do is e3 so he can safely finish development. Notice the tremendous pressure Bb4+ Nd5 exert on the White position by pressuring the dark squares ( c3 and the entire a5-e1 diagonal! ). This is the key idea of Black's defense in this, and similar positions -> to control a5-e1 diagonal and the dark squares. Black is more than fine here and simply playing natural moves should give you satisfactory position. It is White who fights for equality here.

[Title "Tremendous exchange sacrifice for Black"]
[fen "rn4k1/ppp2qpp/4n3/8/1b6/1Q6/P2P3P/RN1K3R w - - 0 16"]


This is one of the variations from the above diagram that is most complex but is easy to play with Black. Black has sacrificed the rook for a knight, bishop, two pawns and exposed White king. The compensation is more than enough and Black has a winning position in my opinion. Just develop Nb8 and do not be afraid of d4, threatening to fork the knights with d5, because you have ...Rd8! which pins the pawn and gives decisive initiative. White can't survive because of his exposed king and lag in development. Again, you are fine.

[Title "White plays the weak f4 attack"]
[fen ""]

1.b4 e5 2.a3 d5 3.Bb2 Bd6 4.f4 exf4 5.Bxg7 Qh4+ 6.g3 fxg3 7.Bg2 gxh2+ 8.Kf1 Nf6 9.Nf3 ( 9.Bxh8 Ne4 10.Bxe4 dxe4-+ ) 9...Qg3 10.Bxf6 ( 10.Bxh8 Bh3-+ 11.Rxh2 $8 Ng4 ) 10...Rg8 11.Rxh2 Qg6 12.Be5 Bxe5 13.Nxe5 Qf6+ 14.Kg1 Qxe5 


The whole point of f4 lines is to accept the pawn, gambit the rook on h8 and smash White in the coming attack. These lines can be tricky so you could additionally analyze them with an engine, just to see how exactly can you capitalize on your advantage the easiest. Again, nothing to worry here, Black has a winning attack.

[Title "White doesn't take the Black's pawn at e5"]
[fen "rnb1k2r/1p2qppp/p1pb1n2/3pp3/1PP5/P1N1PN2/1B1P1PPP/R2QKB1R w KQ - 0 14"]


Here, White is smart and doesn't wish to make early trouble. He will finish development first, and then will try to capitalize on his queenside space advantage. The most typical plan in similar pawn structures is minority attack. That is why Black played ...a6 at some point, to hinder this plan. 

Black will maintain his advantage in center, and will refute any type of wing play White bases. Remember the golden rules:


Attack in the center refutes the wing attack;
Who controls the center, controls the wings too;


I would recommend you to study Orthodox defense of the QGD, and the Exchange variation of the QGD as positional transformations of the above position will have very similar plans like in the mentioned lines. M.Sadler-Queen's Gambit Declined ( 2000 ) is dated but excellent starting point. The book is clearly written and explains all the plans that might crop up here. You might need to learn about Isolated Queen's Pawn, and my answer to this question might be helpful as a starting point. For further reading I highly recommend A.Soltis-Pawn Structure Chess ( 1995 ) as it is simply awesome.

If you have further questions leave me a comment. Hopefully this helps.