Metals are solid, lustrous elements having high densities. These are mostly solid in nature, however, mercury metal is liquid at room temperature.
These are opaque and have high melting and boiling points.
These are good conductors of electricity and heat
These belong to the group 1, group 2, lanthanide and actinide series of the periodic tables.
These have limited number of valence electrons (1 – 3) in their outermost shell and thus losing electrons is much easier for them than gaining electrons. Thus these act as reducing agents and themselves get oxidized. These lose their valence electrons and become positively charged ions, also known as cations.
On the other hand, non metals lack any metallic properties. These mostly occur as solids or in gaseous states, with bromine as an exception as it is present in liquid form at room temperature.
These are soft and lustrous, that is not hard as compared to metals. These are good insulators of both heat and electricity.
These contain more than 4 valence electrons in their outermost shell and hence, gaining electrons are much more easier to them than gaining eectrons. These gain electrons and thus act as oxidising agents as they themselves get reduced and form anions. Melting and boiling points of non metals are comparatively lower than that of metals (however, carbon being as exception to this as it has a relatively high melting point).
Metals form basic oxides (example – NaOH, KOH) whereas non metals form acidic oxides (example – Sulphur dioxide, carbon dioxide etc.). Formation of oxide takes place when a metal or a non metal undergoes reaction with oxygen.
Metals, on reaction with acids, liberate hydrogen gas whereas no such reaction takes place between non metals and acids.
These were a few points differentiating between metals and non metals. I hope this answer helps.