Grain: Try to keep your grain intake low, but for what you do eat, make sure it's whole grain for the most. Gluten free products are still an option as well.
Meat/Protein: Keep your meat intake low as well, as a single serving is roughly the size of a deck of cards. Low fat/fat free and organic is recommended. As for plant based proteins, eat a variety to gain all the necessary nutrients you need.
Fruit/Vegetables: As for both groups, be sure to eat plenty, and a variety of them. Keep the consumption of canned fruits and vegetables as well as fruit juice lower, while organic and fresh produce is recommended.
Dairy: Fat free and low fat is recommended, as well as products fortified with vitamin D. If vegan, or otherwise unable to drink/eat dairy, calcium fortified soy/almond milk as well as fortified orange juice act as a substitute.
Sugars, fats, alcohol, salt, etc: It is not necessary to abstain from these completely. In fact, sugar, fat, and salt are required for bodily function, while a bit of alcohol (specifically a glass of red wine) will positively affect your health. But in large quantities, these can lead to major health complications, so keep your intake low.
While trying to prevent sexually transmitted infections (STI's) will, in theory, prevent pregnancy, it does NOT work in the other direction
Condoms, when used properly, are very efficient.
The only real, 100% guarantee to not contract an STI is to abstain from all sexual contact, including vaginal sex, anal sex, oral sex, dry humping, kissing, etc.
Thinking highly of yourself and your abilities. Don't put yourself down, instead consider how you may do better. Take pride in your work and accomplishments.
Being free of mental illness, or getting treatment for mental illness you may have.