can i keep seeds i have left over till next year ? how would i store them best
Yes, most seeds can be kept for a few years, some last longer than others, as they age I've found less seeds germinate though. The seed packet may have a sow by date on, in which case they are usually good until at least this date but alot last longer.
Keep them in a dry cool place. They are best kept in their packets. I keep mine in a box and away from heat.
Though if they were in foil-lined packets they will start to deteriorate as soon as the air gets to them. Some varieties have to be bought fresh every year, some will last for years.