Motivation is fairly easy to get as long as you have clear goals. On days where I can't find it I take a pre-workout shake called razor 8, it works great.

Crossfit is great, I do it about 3 times a week, I also do a 5 days a week workout developed by the British SAS which damn near destroys me day after day. It's good not to neglect your cardio so I try to go running at least 3 times a week for about 10km per session. Intervals and hills are my thing

It's been said before that diet is a massive factor to developing whichever body type your after and it's 100% true, the general rule of thumb I follow or try to is buying my groceries from the OUTSiDE edge of the supermarket, it allows you to cut back massively on the amount of preservatives you ingest. It is also true that eating healthy is more expensive but you can't win them all.

Something alot of people overlook when lifting weights or working out in general is form. Form is key, you can do 100 squats with 150lbs with bad form and get a back injury OR do 50 squats with the same weight and not only see close to the same gains and yields, but not hurt yourself.
For anyone looking for a real challenge and that is familliar with crossfit search up "fight gone wrong", that'll put some hair on your eyeballs.