Basically moderation is key. People will tell you you can't eat this or that but most things as long as you don't eat a ton of it you will be fine. Probably anything your mom says not to do is an old wives tale!
As far as OTC medicines, tylenol for pain is about it. No ibuprophen or aleve. Tums are great for instant releif of hearburn (I have a bottle in my purse, by my bed, and in my medicine cabinet!). For constipation you can take milk of magnesia or colace stool softeners. No laxatives. You can take claritin for allergies if you have them (I have taken one every day of this pregnancy or I will be a mess!!)
As far as foods...you can have splenda as a sweetener and sweet&low (in moderation), you can have some caffeine (I cut it out completely though just out of fear and because I didn't drink much of it anyway), obviously avoid alcohol although a glass of wine now and then is fine, if you eat tuna limit it to one can a week and avoid other large fish as well. No raw fish as in sushi. Some soft cheeses you are supposed to avoid as well but I can't remember what they are as I don't really eat exotic cheeses anyway! If you eat luchmeat just microwave it until it steams.
Avoid face soaps with benzoil peroxide and salicylic acid
I am sure these will all be discussed in your DDC too...people will be freaking out about splenda and sweeteners and lunchmeat, hair dying, etc. Just remember moderation is key and you will be fine.
Here is a website with a bunch of do's and don'ts
Pregnancy & Safety | BabyCenter