There are lots of different species of tree growing in Glasgow. These come in a variety of different shapes and sizes. To tell them apart you can look at the leaves (arrangement and shape), bark and general shape of the tree.
In the winter deciduous trees have dropped their leaves, which can make you think that identification is harder. But at this time of year you should take a closer look at the winter shoots and buds (young leaves for next year).
A key feature to look at is bud arrangement.
Are the buds opposite each other or spaced alternately along the shoot?