OP the main thing I'd recommend in a machine whatever brand, is to get a top loading bobbin (ie it drops in vertically) rather than a front laoding bobbin.
The thing to realise with sewing is you need to absolutely know some techniques about machine, fabric & pattern fitting.
Techiques include:
How to thread a machine.
How to operate your machine.
Needle down before sewing.
Using correct needle, adjusting tension.
How to wind a bobbin.
These techniques are largely unchanging no matter what you are sewing.
Fabric - how to choose the right fabric for each garment/project to get the effect you need.
Chosing the thread too - as others have said cheap thread is not a great idea.
Knowing about nap etc & cutting fabric correctly.
You can see how less successful garments on Sewing Bee are so often down to the incorrect fabric being chosen for the garment - last night had some great examples of this.
How to fit clothing - knowing most womens patterns are for a certain height body and B cup boobs (thought here are many curvy indie patterns out there these days that cater for larger bust & curves such as Cashmerette). I'm 5'8'' for example and usually have to add length into patterns or they just won't fit. Even as a fairly experienced sewist have had loads of really discouraging fit issues expecially after my body changed after children - so I had a lot to learn about fitting garments for my body especially if using "big 4" patterns.
There are some really great facebook sewing groups you can learn alot from. And many wonderful idie pattern companies.
Fit aside, mostly it's like riding a bicycle - nail the basic techniques and it will get you a long way.