TTC in your 30s

I am a 33 year old mom of 2. I have been on BC (Mirena) for the last 5 years. My hubby and I have decided that we are going to try for baby #3!!!

We had some infertility issue in which the Drs could never give any reason for and I also had a miscarriage during my first pregnancy at 8 weeks. I am super excited about TTC but also really nervous about starting the process and potentially running into some of the same issues as we did our first go around. What advice would you give to prepare mentally, physically, and emotionally for this journey???