This is where payware aircraft really come into their own.
However, in terms of hand flying the approach...just keep practise and make sure you using all the in-cockpit aids as well as visual aids (VASI etc).
My general rule is...
Intercept the localiser at around 170-180 and immediately slow to around 160.
At around 5-7 DME, I lower my last stage of flap and slow to VREF+5 (which on most 737 sized aircraft, is around the 140-150 mark but sometimes less I find). Of course, determining the VREF can be difficult without the correct documentation and payware addons.
Flaps for example help to create lift, to keep the aircraft in the air at slower speeds. Full flaps at 200 KIAS, will not only send you floating away almost...it should in reality do quite a bit of damage to things
On the PMDG 737 for example, I set the speed to my final APP speed and the aircraft will 'retard' the throttles automatically just prior to touchdown.
On any aircraft without this ability...I like to leave the AT on until around 2-3 DME and then take over the throttles. The best advice I can give, is lower the workload as much as possible with what you have.
On a visual, its unlikely you will be exactly centered when the ATC turns you in for final. Too many variables like bank angle, speed, wind etc to allow for that kind of accuracy. Of course, they turn you in and won't clear you for approach until the runway is in sight. After that, it is up to you to line up correctly (and with enough distance to allow for a margin of error) and fly the approach down to the TZ.
I once forgot to call "runway in sight" to ATC, and they sent me on a missed approach
Just keep at it and you'll pick it up in no time.
Flown on: A306 A319/20/21 A332 B732/3/4/5/7/8 B742/4 B752 B762/3 B772/W C152 E195 F70/100 MD-82 Q400