Welcome to OSM, and thanks for your contributions.

Before you upload an edit, I recommend taking a look at the validator warnings (under the "issues" tab on the right pane). It will tell you about potential errors. They are not always correct, but still very helpful. In this case you have a couple of situations where a sidewalk you drew does not connect with driveways/streets, which is an easy fix.

Additionally, you can tag pedestrian crossing ways differently from sidewalks. I recommend taking a look at this guide:
https://wiki.openstreetmap.org/wiki/Foundation/Local_Chapters/United_States/Pedestrian_Working_Group/Guide

Happy mapping!