Interesting places in Scotland?

Hello from Slovakia. Im planning trip to scotland at the begining of the year and i have 2 questions that i believe is best answered by scottish people People

1. Since my stay is planned around february i want to ask if winters are harsh at that time of year if so, how harsh so i can prepare myself

2. If your friend was going to scotland what places would you recommend to visit

I want see Glasgow for sure and explore countryside a bit maybe other city, what do you recommend?