Help me get pregnant now

I need major tips/tricks/advice to conceive as fast as possible.
I have an 8 and a 6 year old already.
But I had two miscarriages and a partial molar pregnancy after.
I'm not sure if that's why we're having a hard time with this.. but we're not getting any younger and I've never felt more financially and mentally prepared. 
Please...any advice helps greatly