I would suggest a bit of compression of the bends on the middle juniper, I don't know how much play is in it but if you could bring down the top it would give it a bit more character...
1) Juniper. Decide if you want informal upright or full cascade. If full cascade I would reduce the top where the direction swings to the right. Then wire and develop foliage pads. reducing the top will also make the tail grow better. Consider creating a Rest so the juniper can lie back once it is watered to let the lower branches develop strength. Keep lower branch tips wired upwards to encourage growth.
2) I find this tree all over the place and you need to decide what style you want and what direction. The trunk has nice movement and direction appears to be to the right. If this is so there is too much strength on the left. Refine your design, remove some excess branches and wire and shape to develop distinct foliage pads instead of its somewhat higgley-piggley growth currently.
3) Azalea. Typical Karume... not a lot to get your teeth into but flowers well worth working on the tree. Once the flowering is over I would be cutting into the tree to remove excess branches and get a design structure, your basic skeleton. If you can plant the tree in the garden to encourage robust growth that would be great. There is one Karume near me that has been in the ground 7 years, has a trunk about 3 cm across and is kept abut 35 cm high and cut to a ball. I tried to buy it but they weren't selling which is a great pity. If you can fatten this up and get your basic skeleton, in a few years it could be a lovely bonsai rather than a tree in a pot.
4) maple - bottom branches are barring so remove the right one since the left appears to have more character. Were it my tree I would reduce the height to emphasise the trunk thickness. First I would cut back to remove the top left angling portion. Next I would probably cut back to the long left branch, encourage a new header and go with the tree at that height.
These are good stock plants and would be great material to take to a bonsai workshop and get hands on help in styling. In most cases you need to remove a bit of the tree to establish the basic structure and the tree's direction. From there you can build your foliage pads. Good fun...
I think the third tree is Anisodotea Capensis (not sure of a common name) not azalea as you described. I have had some bad experience with this temprimental species. The only advice I am confident to write is keep it in a larger pot than it needs (larger than current pot, so repot ASAP), they grow masses of roots and will become pot-bound quite fast.
Best of luck with it, hope you do better that u did.
Trent.
If you wish to bake an apple pie from scratch, first you must invent the universe.
a fair effort there bonsai boy what's the history with these? how long have you been training them ? any before pics? so far mel and scott have given you some great advice.