Change the tactic!
What you have to do is change your tactic a little bit.
your team is not scoring because you are playing to defensive in your formation.
use this formation:
4-1-2-3
4 defenders ( 2 Wingbacks and 2 Central defenders)
1 Central denfensive midfielder
2 central midfielders
3 strikers ( make them complete forwards)
try using this formation:
Casillas
Arbeloa ( try to buy maicon first and then buy rafael ( best RB in the game and young)
Pepe
S.Ramos
Marcelo ( URGENTLY buy LAHM)
X.Alonso
Ozil (buy Luka Modric, not so cheap but you need him)
Kaka ( buy Douglas costa)
Benzema( buy Alvaro from Espanyol, its young but its the best replacement for Benzema)
Higuain( buy Rodrigo from Benfica, becomes better than Higuain.)
C.Ronaldo ( you will never replace him but buy someone like lukaku to replace him sometimes)
subs:
Buy these young players:
-Ter Stegen (GK)
-De Gea/ T.Courtois (GK)
-B. Leno (GK)
-Rafael (RB)
-Van der Wiel (RB)
-Hummels (CB)
-P.Jones (CB)
-Mussacio (CB, Buy him you will need him)
-M'Vila (CDM)
-J.Martinez (CDM)
-F.Anderson (CM. BUY HIM)
-Douglas Costa ( CM,AM. BUY HIM)
-Lucas Moura ( AM,CM. Good replacement for kaka but buy first Douglas Costa.)
-Ganso/Gotze ( AM, CM. Only if you really need them)
-Rodrigo ( ST, BEST REPLACEMENT FOR HIGUAIN)
-Alvaro ( ST, BEST REPLACEMENT FOR BENZEMA)
-Heung-Min Son ( ST, cheap, young, good finisher.)
-Lukaku ( ST, good replacement for C.Ronaldo. Great finisher but Rodrigo and Alvaro are better)
With these list of young player you will have a First class team for like 14 years.
Buy older player because the young players will be good on the begining of the second season but, if you wait to buy them on the second season the will cost 20 Million+ each, don't wait.
Recommendations:
1.-Try buying a first class substitute player for Casillas, like Lloris, Hart or Neuer, they're not cheap but they will be a breath of fresh air on the last 4 months of the season.
2.-Buy Maicon (RB) and Lahm (LB), you will not win in defence without them, remember you are going to change your formation, you will need great defenders. So also try to buy Thiago Silva, Kompany, Terry, Chiellini (cheapest one), and/or Vidic, to help S.Ramos/Pepe.
*** Remember S.Ramos can play as RB too. If you buy Chiellini, he can play as a LB also.
3.- BUY Modric and Douglas Costa, they are much better than Ozil, Kaka, Sahin, Khedira, Lass, etc.
4.- Buy a good replacement for X.Alonso, try getting M'Vila and F. Anderson.
5.- Buy Rodrigo and Alvaro. Trust me they are much better than Higuain and Benzema. Alvaro is always my first option on the field and he did 25 goals in the first season ( I have Ibrahimovic and he did only 15) more than C.Ronaldo (23) and he played less games. Rodrigo did 19 goals in the first season and i rotate him with Benzema.
6.- Sell the players you are not using, BUT DON'T sell Di Maria, Sahin, Ozil, Higuain or Benzema.
try selling players like Callejon, Lass, Khedira, Adan, Albiol, Carvalho, Morata and Granero( they're Expendables).
I hope this helps you. Cheers.