Framing a watercolor will obviously be different from framing an oil. For instance, it is usual to put drawings and watercolors under glass for protection. An oil can be left exposed, so long as it is given a coat of varnish. This does not keep off all the dust from obscuring the painting, but will protect the painting from harm.
It is, therefore, a good idea to clean the surface of an oil painting from time to time with a mild solution of soapy water that is gently wiped over the surface of the painting and gently dried off. If the painting is thoroughly dry before final varnishing (that is at least six to nine months after completion), any wiping of the surface will do no harm. I have even used detergent on a varnished painting with no ill effects.
Before framing drawings, they should be thoroughly fixed, and if the drawing has not been trimmed, the area to be framed must be clearly. marked. The sort of drawings that frame up well will be the bold and vigorous ones. It is a good idea to put up all your drawings on a wall at one end of the room, then stand well back and see which drawings read across the room. This could be done with your watercolors as well.
It is a good thing to have a little private unframed exhibition of your work every so often. It is interesting to see all your works together and you can plot your progress and development. At first it is unlikely that you will want to frame the lot, but you are sure to find one or two works that will warrant it. Then do so. There are always those favorites that you would like to preserve out of a period of three or six months' work.