How to conceive a baby ? How to get pregnant ?

Just wanna know how do I conceive a bby after having a kid for 1 year and a half will it be easier to get preg ? Cuaze I n my partner tried but keep negative I wanna give my kid a sibling But my partner is not the father of my kid is the stepdad he is very good to my kid very loving all is there any way to get pregnant easily