Method of painting -
Both a smooth and impasto (thick) effect is used in my paintings. Oil paintings are undertaken in a slightly 'old fashioned' way, in that I use a formula of painters' recipes of years ago. I use this to mix with my paints, and as a result my paintings appear luscious and bright. However, on the downside, my oils take longer to dry before I am able to apply the next layer of paint.
Hanging paintings -
Suggest you do not hang over a fireplace, do not hang on a south facing wall (southern hemisphere - or northern wall in northern hemisphere), nor in bright light/sunlight. When hanging on walls it is recommended a small 'tack' or even a small piece of board, or pin, be applied to the back at the bottom of each corner, which will help to keep painting away from laying flat on a wall and thereby will allow air to pass behind painting.
Cleaning -
Should your painting require cleaning, ie marks removed, then please do so with a soft, lint-free, damp cloth and wipe gently (no soap or detergents, just dampen with water). If more serious marks or damage, then suggest the painting is taken to a professional art gallery/restorer as they will be able to carry out for you.