You are going to spend a lot of time in the bedroom whether sleeping or relaxing so comfort comes before all else. That requires one thing, a comfortable bed, meaning mattress. If you are starting from scratch and on a budget spend 60% of your budget on your bed, after all, it will be the centerpiece of your bedroom and where you will spend most of your time.
This is important, so I will mention it now, decide where in the room your bed will go. If your bedroom is small you may not have a choice. Choose the widest wall as you will need side tables and make sure you have wall sockets for table lamps. Look where the light falls from your bedroom window and place your bed to the side so the light falls across the bed. If you have a fabulous view you might want to face the bed looking out.
Bed linen for comfort and covers with accent colours. Texture can also play a roll. If you choose a neutral scheme a textured cover can add depth and warmth and be restful on the eyes. Cushions on the bed are an easy way to add comfort and colour to a bedroom.
There are so many ways to add colour to your bedroom. Paint is the easiest. Plan your colour scheme in advance. If you have a headboard on your bed keep the walls one colour. If you do not have a headboard then you could paint the lower section of the wall a different colour that will contrast with your wall colour. Your walls will be the main colour so unless you want a statement colour choose neutral tones then you are free to splash colour elsewhere.
Avoid cold floors such as marble. Wooden floors are ideal or fully carpeted. You will want to be barefoot in the bedroom for warmth and comfort. Add rugs to wooden floors and position them at the foot of the bed or if they are particularly large, partially place them under the bed.
Lighting will be important, especially at night. Good reading lights are essential so make sure side table lights have the required illumination unless you are reading off a backlit tablet then they need not be bright. Use stand alone floor lamps which you can move around as needed to add depth and interest.
If your bedroom is large introduce some furniture such as an accent chair in silk or velvet if you are going for a luxe boudoir look. In a large bedroom you may want a writing desk and chair but try and avoid turning your bedroom into an office during the day unless your bedroom can take it and you have nowhere else in your home to work.
If you have the budget, go for flowing curtains in silk or voile to give a really light and airy feel to your bedroom. Sadly, there is no such thing as cheap curtains. Try looking for curtain fabric in an outlet where you will find end-of-line and prices to match.
To finish off, you may already have some artwork or photographs which you can arrange around your headboard which will accentuate your bed as the focal point in your room.