IT may seem like a no-brainer. You have a Christmas tree. You put stuff on it. You turn on the fairy lights and voila - why does it look nothing like the ones you see in store windows?

Some of the common mistakes people make when decorating their own Christmas tree include cluttering it with too many different shapes, colours and textures that make it look really messy, says architect-turned-floral designer Harijanto Setiawan. Mr Setiawan runs his own floral design business, Boenga, on top of Au Petit Salut restaurant in Tanglin Village, and specialises in unconventional Christmas displays for his commercial clients.

'Sometimes, people put the fairy lights on last, such that the wires are very obvious and spoil the look of the ornaments,'he adds. 'Either that or they don't use enough lights, or the lights and ornaments are unevenly distributed.'

Whether you've just got yourself a tree or have been decorating it for years with an eclectic (read totally unmatching) collection of ornaments collected on a whim over the years, it's time to get yourself organised and completely re-think your annual decoration exercise.

If you're a forward planner, you would know that it's always best to build on a collection, rather than trying to achieve a different look each year. Going for gold one year, then blue and silver in another and then burgundy and red in a third is an exercise in impracticality unless you have a really huge storeroom at home.

Trying to save money by buying cheap throwaway ornaments is another mistake. You always wonder the next year how you could have bought something so tacky, and then go out and repeat the same process. It's best to shell out the cash to buy a few really nice timeless pieces, and then build up your collection each year so that you can have an elegant, timeless looking tree, not a People's Park Complex extravaganza on branches.

So that said, where do you start?

First, pick a tree. Here, there are several schools of thought. Says Mr Setiawan: 'Real and artificial trees have their own advantages and disadvantages. Artificial ones can be recycled but it can be quite unpleasant to look at because it looks so plastic.'

But if you're going to get a fake tree, get a Noble fir lookalike because 'real or artificial, Noble firs have the bushiest foliage and are easiest to decorate - they're beautiful enough even without a lot of ornaments. But live trees are more special because of the fragrance - then again, because of their varied shapes, they can be harder to decorate.'

Once you've picked a tree, decide on a theme.

'If you're a young couple or single who likes to throw parties, pick a contemporary decor theme that portrays glamour and sophistication,' suggests Sebastien Jek, senior merchandising executive for Tangs. 'A suitable colour theme could be jewel colours from rich purples to warm berry tones, cobalt blue to deeper indigo, accented with bronze and gold. Feathers in deep red and black would add elegance to the tree.

'Families, on the other hand, can go more traditional with red, gold and green. Those with young children at home could have a colourful and fun Christmas tree with child-friendly ornaments like fabric or acrylic characters like angels, Santa, Rudolph the Red Nose Reindeer and Frosty the Snowman.'

If you're into trendy colour themes, Mr Jek adds that this year's themes lean towards rich, opulent colours, 'hand-crafted folk art that are vintage inspired and strong jewel colours like purple and gold'.

Then again, themes should really depend on one's personal taste, says a spokesman from Club 21 Gallery, whose trees this year feature whimsical fantasy creature ornaments as well as classy glass baubles.

'Most of our customers have a theme of their own,' says the spokesman. 'While some opt for glamourous clear glass, some pick silver or even red as their theme.? It doesn't always have to blend with the interior decor of the house.'

The most basic thing you have to get right with the tree, though, is the lighting. 'Our lights make the tree look three-dimensional because of the way they stretch in and out of the tree instead of just around the tree,' adds the Club 21 spokesman. 'To keep the tree interesting, use a variety of shapes, such as tear drops, long oval shapes, etc. You don't have to stick to shiny balls only.'

Don't use too many colours, either, he advises. 'It's best that colours complement each other. The decorations can be placed all over the tree - on the branches and inside, not just outside and around. This gives the tree more depth and creates a 3D effect. In addition to ornaments, use ribbons, bows, fake flowers, twigs, fake squirrels or birds to soften the look. And for the lights, it's best to stick to one colour instead of multi-coloured lights. It's a stronger and more chic effect.'

Indeed, achieving a multi-colour effect is trickier than sticking to just one or two colours. If your inner child still loves the blinking of varied colours, then don't use colour as your theme but perhaps a subject, say vintage, or the 12 Days of Christmas, and pick ornaments accordingly.

Ultimately, of course, it's your tree, so do whatever you want with it that makes you happy. All you need, say the experts we spoke to, is to follow some basic instructions, which are, in a nutshell:

1) String the lights first.

2) Divide your ornaments according to shape, size, colour and quantity so they can be evenly distributed, says Mr Setiawan. Use the ornaments that bring out your theme first, suggests Mr Jek, 'starting from the biggest to the smallest, one design at a time, to make sure they are nicely spaced out'. Smaller ornaments should be higher on the tree, followed by bigger ones lower down.

3) Now add the accent pieces, like ribbons, bows, pearl strands and the like.

4) Now it's time for the fillers, like acorns, holly, poinsettia and so on.

5) Top the tree with a nice adornment. Cover the tree stand with a tree skirt if desired.

6) Turn on the lights and pretend you're at your own lighting up ceremony.

7) Enjoy.