Hi guys i need some advices please.

[badlinus87]

Hi to everyone.
I'm Linus and i'm italian.
I never had problems styling hair, until i decided to change from messy spiky hair to a Modern slickback.
I really love this haircut, but something is wrong in my hair. I made this haircut last week and i have 2-3 inches of height
I have straight and maybe fine hair (i think that i have fine hair, because they mess very easily when i style it, or for example they began weighted if i use any conditioner ).
I have a very large number of products (mousse,hairspray,volumespray,greasywax,waterwax and gels,saltspray and prestyling spray like reuzel grooming or suavecito grooming spray or byVilain sidekick) because until now i thought that the problem was the products.
I describe my usual routine to see if someting is wrong:
1)Hairmousse on damp hair (to bring volume) and then brush first with a paddle brush and then with my hands (i like the natural look using hands instead of comb or brush)
2) Suavecito firme hold on hair previously brushed
3)Finishing with hairspray.
Now the problem is that at this point i have a very good result sometimes, but after max 10 minutes my hair began to fall on sides and all the work was lost :-(.
There are some advices for me guys?
thank you