Also, check out our great resources for weight loss - articles and recipes galore. You are correct, hormones can impact our metabolism and weight. Infertility can stem from being either overweight or underweight so depending on where your current weight lies might dictate weight loss or not. Please discuss specifics with your fertility Dr. I will say that specific nutrients are required for health and childbearing so it is ill advised to go on a restrictive diet when trying to conceive.
And finally, check out the top 5 things to avoid here: http://www.nutriliving.com/blog/top-5-things-avoid-healthy-pregnancy
Infertility issues stem from a variety of reasons and without knowing the root cause I cannot provide specifics. I will recommend a wonderful book for a resource called Brighton Baby by Roy Dittmann, OMD, MH. If not done so already, I'd suggest getting some blood work done (hormones, any nutrient deficiencies, etc.) and visit a specialist who can perform an ultrasound to see if there's an underlying physical condition. It is also important for your partner to get a check up as well. Eating a healthy diet filled with a variety of plant-based foods in general can help balance hormones and keep you at a healthy weight - all which are helpful for conception!
For 7 general getting-pregnant tips, check this out from our friends at Food Matters: