ttc for 4 months what can i do to get prego faster

Hi guys i never post on here but me and my fiancé have been ttc for 4 months now i was on Nexplanon birth control for 2 yrs it was spose to b 3 but i took it out early cause i wanna have another baby my daughter is 3 and i want another one but its been very hard to conceive  so dose any one know y this is happening i got checked and my ob said i was fine and i got my fiancé checked and they said hes fine dose any one know whats going on and what i can do