At your trainings, fielding drills become very important in building your team's skill level. This is the only form of fielding practice you get apart from match day, so it is important to treat it as seriously as possible. You will get a lot more out of your practices as a result.
Ground fielding/ high catches
Split your team into two groups, even numbers on each side. Have your wicketkeeper, a single wicket and someone who can hit well with a bat about 40+ metres from the fielders.
The aim of this drill is to work in pairs, practice loud calling and backing up each other. The batsman hits a ball either along the ground, softly or powerful (mixing it up is a good idea). One of the fieldsmen calls for it if it's a catch, the other stays close in case he misjudges it. Whoever catches it passes it to the other fielder, who throws it in the wicketkeeper. Aim to return it over the bails.
With ground fielding, this is where backing up becomes important. One attacks the ball and aims to gather and return it to the wicketkeeper. The other backs up behind him, in case the first fieldsman makes a mistake. Misfields can happen often, so be alert!
A slightly different version of this drill is to vary the fielders' positions. Think of a soccer formation, for example 3-4-3. So have three close, some in the middle and a couple further away. This exercise means you have to call loudly, as a catch might be close to another fielder as well.
Close/ slip catching
This is a fun exercise, and works best with 6-8 people. Stand in a semi-circle, with a batsman in the middle. All fieldsmen prepare as if they were in the slips, ready to take a catch at random. There is a top and bottom in the semi-circle. If you drop a catch, you move to the bottom. If you misfield one, you drop a place down. The aim is to stay at the top for the longest time possible. The batsman should increase the difficulty for the fieldsmen at the top.
A good way to finish a training session is to aim for 20 catches in a row, and if someone drops a catch you start again. Once completing the 20 catches, you get to go home!