Any tips on getting people to play together in a squad on Battlefield 2 (or 2142)?

I can only provide you with some suggestions;

1. Try to find servers that are focused specifically on team work, search for these on Google or websites dedicated to Battlefield multiplayer.
2. Contact players whom you've played with that have an interest in team work like yourself and play together frequently on the same server. This is often easier if you know the players i.e. work colleagues, friends etc.
3. Do try and lead, You can often surprise yourself with how well you can organise things with complete strangers. If you do a job that involves managing different people e.g. emergency services worker, then you will already have the skills to do this. If you are not then doing this can still be very beneficial because it will give you an outlet to practise and improve your communication and logistical skills.

Hope this helps.

Surprisingly nobody have mentioned the most obvious course yet.

Join a clan

There are plenty of clan servers out there and a lot of them advertise openly that they are recruiting. A clan is a group of people that play together for improved teamwork and fun. They can be relaxed/causual or dedicated/hardcore or anything in between. You just have to find one that match your dedication.

It's much easier to join an existing clan than trying to start one from scratch!

Edit:

Some things I would look for in a clan (your preferences might vary though):

1. Democratic rule with no leader. This is gaming with friends, not the military.
2. 18+ age limit.
3. Clear ethics regarding behaviour and rules of conduct, but no public whining when outsiders don't play according to their morals. In other words friendly and honorable.
4. No required playtime, required meetings or other silliness.
5. Roughly the same time zone.
6. Required VoIP.