I have played about with ldd,  and built a small project, but I am finding limitations. Often it is very hard to slot pieces together accurately. I have most of the functtions, but this lack of accuracy is annoying. Does anyone have any tips or can you suggest another app?

There are many differing opinions on this, but if you're just starting out I wouldn't pick LDD to invest time in with it being dead (no longer supported or updated) and would instead go for something in active development with a broad user base, like Bricklink's Studio (www.stud.io).  There are several other good programs out there, but unless there's a specific feature of LDD you really love or need that Studio doesn't have, that's a good way to go.

2 hours ago, deraven said:

There are many differing opinions on this, but if you're just starting out I wouldn't pick LDD to invest time in with it being dead (no longer supported or updated) and would instead go for something in active development with a broad user base, like Bricklink's Studio (www.stud.io).  There are several other good programs out there, but unless there's a specific feature of LDD you really love or need that Studio doesn't have, that's a good way to go.

LDD is being updated by the community, literally on this very forum... 

There's a lot I think I love about ldd, but I can't compare it with anything. I love the way I have got to know it pretty well! But I find it difficult positioning pieces. Maybe it's me, maybe it's my laptop settings, specifically touch pad, maybe it's LDD. Do other people find it better to use a mouse for manipulating pieces? I know the mouse keyboard combo right cick + shift allows panning around the model, which I can't seem to do with the laptop alone.

Any other suggestions would be welcome. LDD has given me confidence that I can use this kind of software, but it would be a shame to abandon it, all the shame.

Then it's definitely your touchpad. Try it with a mouse. LDD has very easy snap behaviour, so you shouldn't have this much trouble.