+1 for what Woodnthings said.
Also search on this site for jigs, tips, etc. Helps if you know a specific jig.
For sharpening, this could be a forum by itself. For some this is almost a religion.
Do a search for "Scary sharp".
It helps to have a flat reference surface. Some people use a thick piece of glass. Others use a granite slab. Adding this link so you know what to look for. I do not know who will sell such an item in the UK.
You can also purchase water stones and sharpen on these.
Another link for reference.
I use a granite slab with wet and dry paper of different grits and the Lee Valley honing guide.
Hand cutting a straight saw line will take practice. One trick I read in a magazine which helps me to cut on my bandsaw is to draw TWO lines. Something about our brains, it is easier to follow a track between two lines than it is to keep just to one side of a single line. After reading this I tried it and for me, it made it easier to get a better cut on the bandsaw.
I have tenon and small cross cut saws. I only use these for cross cuts on small pieces, too small for the table saw.
Getting a flat surface with a hand plane will also take practice. Lots of videos are available. You do not state the size of the plane. If the plane is small/short and the piece is long, it will be more difficult to get the piece consistently flat.
When it comes to planing the edge of a board, I can get the edge flat and straight, but I still struggle to get it to be orthogonal (90 deg to wide surface). I ended up getting this aid. This was an improvement, but I normally just make the cut on my table saw.
Take a look at the Hand Tools forum on this and other sites. There are a number of hand tool experts around.
I love my hand planes, note the plural, but I am happy to also have my power tools.
Many threads on various sites about which "single" hand plane. I think one on this site. For me, I could not imagine having only 1 hand plane, since certain tasks like cleaning up the bottom of a dado require a specific plane design.