There are lots of tips to give you about turnout building/track laying but I will confine myself to two of the less repeated plus the best way of finding out if you have problems.
Tip 1 - ideally by using Exactoscale gauges (https://www.ebay.co.uk/itm/355438945630
- although they are generally cheaper than this on ebay) ensure that the plus +0.1 guage goes through the switch easily. I find that with both premade and handmade switch rails, there is a tendancy for them to flex out as they are assembled such that it appear as if they are to the correct gauge but in reality are not. The use of the +0.1mm guage hels.
Tip 2 - when you lay track use Peco bullhead or DCC Concepts fishplates as you would with OO track. They help the alignment of the rails in both the horizontal directions which is often rather lacking with hand laid track and even the odd 1/10th of a mm is enough to cause bother in P4
Best Test - get yourself a mint gauge (in the stores ref RSG). It should slide through trackwork and pointwork without stiffness or slopiness. If it binds or starts to need a lot of force to get it through, the track is undergauge and if you can twist or rattle the gauge it is too wide. It is also a fairly chunky bit of metal so if there are any high chairs or similar, it will remove them for you!
As a small PS; make sure that you keep the mint gauge clean as it can get clag on it. Someone who will remain nameless (but might be our chairman) had a little issue about this recently - my gauge went through the track and his didn't - until he cleaned it that is!