When it comes to moving your little one from your bedside to their own bedroom, and then from a crib to a 'big kid' bed, there really are no rules. Each child will adapt to these changes differently. Location (or proximity) of the bedrooms, and whether or not your child has siblings can play a big role in the transition, so first thing's first - try not to panic! Whether your little one is 2 and already sleeping in their own room, or they're 4 and still sharing with you, you're doing a fantastic job.
Finding the right time
Toddlers have so many milestones to overcome, it can be difficult to find the right time to introduce them to anything new. Most parents will have their children sleeping in their own rooms and big beds between the ages of 2 and 3 1/2, during which time you may have potty training and first days of pre-school to deal with. Truthfully, there's never a right time for any of these things, but finding a gap when a few of the other milestones have been achieved is a good start. If a new baby is on the way, try and have the transition complete before their arrival to avoid any cases of sibling jealousy stemming from the fact that he baby is now sleeping in your firstborn's crib.
They might surprise you
If there are fewer changes happening in your little one's life right now and for the next few months (as far as you know), try and let them take the lead on this. They might just surprise you one night with "when can I have a big bed like yours?", and this miracle would save you a handful of complicated bedtimes.
Dropping a few hints about how big they're getting and how small their crib is compared to your big bed might steer them in the right direction.
Encourage playdates with relatives/ friends who have big kid beds
When your child sees that their cousin or friend has a lovely big new bed, with fun bedding and all that space to roll around, they should be easily convinced to make the change themselves. Take them for a playdate, and be sure to make a fuss about how 'grown up' the room is, then get building! If you decide to go away on vacation/ for a weekend, try and get them to sleep in a single bed as a treat, and then suggest they have their own when you return home.
Let them be as involved as possible
From flicking through a catalog to a family trip to a homewear shop, let your little one be as involved as possible. Choosing their own bed, bedding, and maybe a few new soft toys will keep the momentum going. They might like to watch you take down and remove the crib, or they might be happier for the new bed to just appear ready-made one day. You know your toddler's emotions better than anyone, so we'll leave that decision up to you. If possible, place the new bed exactly where the crib used to be to avoid too much change, but ask them if they'd like it moved somewhere else if they're comfortable with it.
The same routine
The only change in this situation should be the actual place that your little one is sleeping. The bedtime routine and the rest of the room should remain the same. This is a big change for your toddler, so if you suddenly decide to read 3 bedtime stories instead of 5, or assume they're ready to have the night light switched off at bedtime, you may be causing too much unbalance. You want your toddler to feel as comfortable and safe as they did in their little crib, so consistency is required.