So you buy a nice two shelf bookcase but it’s wobbly and you know it won’t hold much. I’ve recently gotten one and my solution was to put L-brackets on it. After installing about 8 of these brackets at the cojoining parts of the shelving, it is now completely stable and ready for use.
If you’re buying packaged stuff, buy it in the hard plastic containers, not the soft plastic bags. The hard plastic protects it much better during transit, and can easily last a week for me before getting soggy and gross.