The bridge

Make sure your bridge is straight. It takes a lot of pressure and is submitted to a forward pull when you tune your strings at the pegs. As a result it can start to lean forward, warp over time and eventually fall over or break. The back side of the bridge (towards the tailpiece) should be flat and at a right angle to the violin top. The front is slightly arched for more stability. Have your teacher or violinmaker show you how to straighten your bridge. If it's already warped your violinmaker might be able to bend it out. The tendency of the strings to pull the bridge forward will be bigger when they have cut deep grooves in the bridge, because they can't slide through the grooves easily enough (this can also damage the strings). Especially on the thin strings, have the groove protected by some parchment and/or use the little protective plastic tubes provided with your strings. Sometimes, usually after receiving some kind of knock the bridge can also move sideways. You'll notice that, because the strings will be moved to one side of the fingerboard. Take a note of where your bridge is and show it to a violinmaker if you think it has moved they can easily correct it.