The advice I would give you is:
- start small.
Most of the time, people want to try out the big and fast birds first. I did that as well back in the days. If you are new to aviation/flightsim and want to take it to a bit more serious level than landing a 747 on Lukla or taking of with a f18 from Courchefell; hop into a cessna or other single engine prop without glass screen. Take off from a airport nearby your hometown, try to navigate visual to familliar places and once you feel like it, try to level the plane at a certain altitude, with a certain speed on a specific heading/course without giving a lot of input from the controls. trim the plane and enjoy the “look mom, without hands” flying. fly as much circuits as possible so you can almost blindfold land the plane. Try crosswind landings and master the art off crabbing etc. Learn about navigation and try a low vis/IFR flight and feel the thrill, when you see the runway lights from your destination airport at the expected moment instead of inverted carlights during “cruiseflight”.
- Study
Buy a real life aviation study book and watch youtube or streams. I come from a time the only information about aviation was 1 book in the local libarary or at the local flyingschool (45km bicycle away). Nowadays you are flooded with information one mouseclick away. watch tutorials (including real life ones) and try to replicate those flights and techniques. Fly the tutorial flights in MSFS or watch the MSFS twitch streams where Jayne learns to fly.
- focus on 1 plane
After you get the basics, focus on 1 plane and master it. Choose your favourite airplane (tubeliner, multi-engine prop, etc it doesnt matter) and try to learn everything about it. If you go for a tubeliner, you can start with a default one, but try to hop to a more advanced/modded one as soon as possible (the free FBW A320 is a nice example). otherwise you might get into habbits/flows that are not easily to get rid off.
This way you enjoy flying your favourite plane and gives you enough perseverance when you undoubtedly bump into complications or having minor setbacks.
- Have fun
It sounds like an obvious one, but sometimes this one is forgotten very quickly. Do everything in your own pace, dont rush your learningcurve and dont get demotivated by others. If you want to buy/fly a “studylevel” plane as a rookie, go ahead. If you want to fly a 747 under the golden gate bridge: awesome! What?, you want to take a glider up to the stratosphere and end up with a 45 min airshow, all is fine. Just as long you have fun. You want to take it to a “professional” level? Study, read and dont be afraid to ask for help. Experience your first (most likely nervous) online radiocall on VATSIM and enjoy the virtual skies with thousands of others.
- real life flightlesson
take a real life introduction flight or flight lesson. Just one is allready enough to get yourself occupied for many hours afterwards. Bring a camera along and try to evaluate afterwards. keep an eye on the instruments and ask the instructor everything you can come up to. Make a list in advance and come there fully prepared. You wont regret it!
To answer your first question about suitable airports/route:
- if you fly general aviation, choose a airport nearby your hometown or other familiar place.
- for bigger/fast airplanes/tubeliners and world/simupdates, my testing route is Rotterdam (EHRD) - Heathrow (EGLL). A nice alternative for Rotterdam (Rotterdam has a smaller runway and is not so suitable for 777/747 landings/take offs) is Amsterdam (EHAM). With a 737/A320 it takes about 30 - 45 min and is just long enough to get a small taste of cruise (mostly around FL240) and gives you enough time to set everything up for approach and landing without any dull/boring time in between. Also weatherconditions and winddirection may vary a lot on this route so always a surprise what approach/challenge you will get.
- if you use the FBW A320, PMDG 737, Fenix A320 etc, plan the flight via simbrief, so you dont have to worry about what flightlevel etc to choose
- if you want/need some personalised help, feel free to sent a DM