The height of the chair and the ottoman should be match up to perfection. Yes, you'll need to measure your chair and shop according to those measurements, otherwise the comfort bringing purpose of the ottoman will be slightly reduced. It is only a matter of taste whether you should choose round ottoman furniture or opt for other shapes.
Sometimes when buying from the same manufacturer you might get lucky enough and find out that there is an ideal, specifically made ottoman to match your existing chair. If that is not the case, you can look for the nearest ideal fit by matching the fashion concept of both pieces of furniture. This means that they should both fall within the same category if discussing the atmosphere the create, whether it is more on the old-fashion, modern side or something in between. If you are up for some bolder move and want to experiment, look for ottoman furniture its features and look that might fit different types of surrounding furniture. Keep it simple and neutral and you'll find a blessing in disguise. The more neutral the piece, the more you will be able to match it again, for instance if in future you decide to change the chair and the couches.
Mismatch the texture of the chair and the ottoman and you're looking at a living room chaos. To avoid this, simply follow some basis ground rules, do not mix microfiber with leather, or silk with linen and you'll be on the safe side. Succeeding to match the texture of both pieces will result in a classy living room feel.
Matching the color of chair and the ottoman furniture is the easiest part of the deal, since a little difference in the color might even freshen and enliven he whole look of the living room.
If you try to adhere as much as possible to the above described tips and if you try to be patient and make a thorough search before purchasing something you'll regret having in your home, there won't be any need to camouflage the mistakes. If you want and need to add more practicality to your home as well, opt for storage ottoman furniture and have some dear items discreetly put away inside you favorite rest stop.