The honest answer, dont, unless you have been shown how to properly. Depending on your breed you may get away with a tidy around the edges. The best thing to do between grooms is to ensure that your dogs coat is thoroughly groomed and all knots combed out. This maintains skin condition and keeps a healthy coat, and ensure that no breakage to coat happens by the groomer having to de-matt the dog prior to there hair cut/style.

If you are very careful you can cut the hair around the edge of the feet, using sharp straight scissors horizontaly around the edge and thinning scissors to take the hair from between toes.  This is acheived by pulling the hair up through and trimming the excess pointing the scissors facing font, be careful not to catch the knuckle.  The hair around the eyes is a tricky one, you should use rounded thinning scissors and point toward the nose and out from the corner of the eye, only trim the very smallest of hair from the corner and NEVER take from below this as the hair will grow back towards the eye causing an irritation.

Staining in white dogs: this is a problem found in a lot of breeds, staining around the eyes and mouth, there are many products available to remove this, but most have a lot of chemicals in them.  When cleaning the eyes use only a damp cloth and a comb, comb away from the eye and only wet if you need to, it is due to being consantly wet this staining occurs.

Some breeds all they need is a good brush through once or twice a week, other breeds need clipped or trimmed every 6-8 weeks, others every few months, some breeds need hand-stripped a couple of times a year. Depending on you breed and your lifestyle and also the amount of time you put into the maintenance of your dogs coat, will determine the cut or groom your dog can get at the groomers and in turn will determine if there is any parts of this styling that you could do at home.

You should speak to your groomer about this and they will tell you the best thing to do. Some groomers have training days for pet owners to give them the basics on how to maintain their own pets coat.