Like others have said - be consistent! We take our 7 month old outside at the same time (roughly) in the morning, afternoon and evening. We also have a "catch phrase" for her. For instance, we leave the house at 6:15 a.m., walk the same route, and when she pees we say, "Take care of business!" and then praise her excessively. I am certain that I look like a crazy person, but I am fine with that
The process is repeated a few hours later when my husband gets up, again mid-way through the day and twice more - upon my arrival home from work and then during an evening walk. We are outside A LOT!
We were concerned with potty training only because Frankie is a rescue and we weren't sure how she'd adjust, but she has been doing beautifully! (We've only had her for 3 weeks)
If she does potty inside, just calmly scoop her up and take her outside. If she potties again outside, praise her. I also use praise and pats more often then treats. I don't want her to associate going potty inside with a trip outdoors and a dog treat - if that makes sense.