The most important element of interior design would be a functional space. Functional space acts as the base of the entire interior design. Therefore, it is essential that the user and designer both are well aware of the space availability and purpose of each individual space. A functional space would contain two type of space; A space that is filled with furniture or fixture (e.g. sofa, dining set, and etc.) will be a positive space and a space that is empty (e.g. hallway, space between dining set and sofa) will be considered as negative space. Both spaces are determined by the user's needs as every user will require different space for variant purposes. Most importantly, both spaces should be well-balanced maintained as you do not want to be overcrowding or emptiable.
After functionality of the space, next thing to take note would be colors. Colors represent an aesthetic connection between the living and non-living object. Choice of colors can also be psychological affection to individual mindset attached to the functionality of the space. Each color has three distinctive aspects of Hue, Value, and Intensity. A good interior designer must be well aware of these three aspects to perform all kind of pairing alterations or combinations of the colors. For example, light earth tones (e.g. beige, light brown, light warm grey, and etc.) would be an excellent choice for bedroom as it is the color of the harmonious blend as a neutral base evocative of stability which is great for making any room into an oasis of peace with a warm and inviting environment.
Each interior design project is personalized for the owner, beyond just catering to their aesthetic taste and style preferences. Regardless of the project residential design, hospitality design, office design or retail design, you would like the building design to represent a brand or preferred taste of the owner. Therefore, understanding the different design style would greatly help you to proceed to the next stage to finalize the overall design style. For example, minimalist would prefer design style that is minimal and with the balance of both positive and negative space whereas classicalist would be highly favored into the classical edges detailing of each piece of the fixture in the interior design from ceiling to flooring design to establish a very classical grandeur interior presentation.
Light is one of the most critical elements of interior design. Either artificial lighting or natural lighting, no elements would be identified simply without the light. Light sets in the mood and ambiance into space together light will also highlight some of the other design elements with the prior to proper planning. Therefore, you may refer to the three major types of lights - Mood Lighting, Accent Lighting, and Task Lighting.
Mood lighting also referred as ambient light which generally set the mood of the general space and illuminate the overall space that set the mood. Mood lighting commonly refers to cove lighting on the ceiling, floor lighting or wall lighting that illuminate the overall space of the dedicated mood.
Accent lighting also referred to focus light which generally set to highlight a particular element or object. For example, painting artworks, design structures, sculptures and etc. You may found ceiling spotlight, track light or integrated lighting design would be a great way to function as accent lighting.
Task lighting as the name implies, includes light sources like table lamps and bedside lamps which serve a defined purpose or dedicated to a specific task. For example, table lamps for better reading or writing purposes for the work desk and bedside lamp would be great for soft lighting without opening the general lighting that might annoy another party in the room.
Last but not least, natural lighting would be the best of all as it will not cost you and eco-friendly that serve the same purpose of the artificial lighting. If the owner or designer could integrate the natural lighting source design into the building then it would be the best design by using the natural resources.
5) TEXTURE & PATTERN
A different material would have different texture or pattern that would bring interesting feels to interior design along with the element of colors. Different texture or pattern would add depth to a space together it will define the feel or appearance. Texture or pattern could easily found in all aspect of design especially interior design with the designated flooring material, wall finishing, choice of cushion, bedding material or furniture's material. Most importantly, always strike a balance with the overall composition of the space without being too much or too less. P.S. Remember the positive and negative space mentioned on (1).
Whatever you do just remember be flexible as nothing is absolute!