Anxiety

I have a Flat coat retriever mix, she is 1.5 years old. We live in The city, She is very nervous when outside, bikes, strollers, luggage all make her very anxious. She has also become timid when meeting new dogs, she was always cautious but quickly became comfortable and ready to play. Now she lays down for them the smell her and takes more time, if she does become comfortable. I want to help her, she is lovely and playful, I want her quality of life to be amazing. How to I help her be brave and confident?
Thank you
Melissa