How to Plaster
Plastering guide is here to help
Mix up the plaster - thick enough to keep its shape but easy to spread like soft butter
Spread evenly as possible onto area, approx 2mm thick, using a Hawk and Plastering Trowel
Do Not try and flatten out all of the lines when spreading your plaster, let the plaster dry a little keep checking it with your finger tips, when it stop sticking to your finger you can flatten out the lines with your Trowel, timing is key here, too wet and you will see puddles of watery mix forming in areas or bubbles forming in areas, this is air trying to escape, the drying process between laying your plaster and pressing your plaster flat is very important, when the plaster is applied to the wall it should be done as quick as you can and then you can rest for 5 mins or 10 minutes before pressing down, if your laying a wall i personally think laying the top half and then laying the bottom half is best practise, you should not be attempting ceilings if you are new to plastering, there is high risk of getting plaster in your eye when laying plaster on a ceiling.
So you have laid your plaster left it dry and then pressed it down to smooth out the lines, also fill the holes if any, don't worry about the rough texture or the fine lines you can see, the next step is second coat, lay the plaster the same as before but you use a little less and mix it up a little wetter than before - Not Runny! and again you have to lay quickly and leave to dry for 5 or 10 minutes remember to use your finger tips to check the plaster, and always check where you started because obviously it will dry in the same order you laid the plaster if the background area is the same, i.e. all plaster board or all pained plaster with PVA primer coat, check it as soon as you finish laying because if you have taken 20 mins to lay the plaster it might be ready for pressing down flat at the beginning.
Now you should have laid your second coat let it dry a little and then pressed it down flat, at this stage you should see a significant difference in the smoothness of the plaster, Do Not press the plaster too much with your trowel, your trowel should not go over the same bit more than 3 times, with each stroke of the trowel you are compressing the plaster and squeezing out some water, if you do this too much it will cause problems with texture and shape of the surface
You don't have to worry about the fine lines you can still see on your plaster because the final process is troweling up, after you have pressed down your second coat give the plaster another 10 mins to dry and then brush with a Soft! Clean! Damp! brush and press the plaster with your trowel again, you should see a very smooth texture after your trowel goes over it and a huge line of sloppy plaster left behind from your trowel, by now you should have learnt to get rid of these lines as you press down, overlap your trowel strokes and add more pressure to the back of the trowel, so the front of your trowel is doing the blending work, at this point it should look like its finished and your thinking of leaving it but you should give it another 5 to 10 mins and then you can press it down with a dry trowel to squash out any bubbles forming or lines left from troweling up.
Don't forget to use a 1 inch soft brush to keep your corners clean and sharp!