how tall should a coffee table be?

Most settle around sixteen to eighteen inches high. The exact measurement depends on the seat height of your sofa. You want the table top level with the cushions. Older cut-down pieces vary wildly. If a dealer chopped the legs off a Victorian dining table in the 1960s, it might sit a bit higher or lower than a purpose-built 1930s piece.

i inherited this dark wood table that sits really low in the middle of the room and im wondering how to clean the sticky surface without ruining it?

Start with a damp cloth and mild soapy water. Wipe the sticky areas gently and dry them immediately. Don't let water pool on old wood. If the grime remains, a specialist wood cleaner formulated for antiques will break down the old wax and dirt. Apply it sparingly with fine wire wool in the direction of the grain. Once it feels smooth, apply a thin coat of clear beeswax. Buff it off after twenty minutes to protect the finish.

do glass tops scratch easily?

Yes, old glass picks up surface scratches from ceramic mugs and metal trays. These faint lines accumulate over decades of daily use. You can't remove deep scratches from antique glass without distorting the surface. Most dealers leave them alone and consider them part of the age.

my living room has quite a small gap between the sofa and the television stand so would a rectangular or round table work better for getting past?

Round tables work best in tight spots. The lack of sharp corners makes slipping past much easier on your shins. They also visually soften a room full of square cabinets and straight sofas. Rectangular frames maximise surface area but demand clear walkways. If you only have a narrow corridor of space, an oval table offers a sensible compromise between the two shapes.