- Drink.  Lots.  Of.  Water.
  - Get your electrolytes.  Propel and Powerade Zero can be good for this, though you can take pill supplements.  Some people say to avoid diet drinks – I've had more aspartame than most human beings and have never had any issues.
  - Get your magnesium.  You can of course get a supplement, or you can include things that have magnesium like spinach in your diet.
  - Make sure you're not iron deficient.

Other random thoughts:

  - Intermittent fasting seems to help me get into ketosis faster.  It also has multiple benefits that are good for both in and out of ketosis.
  - Don't bother eating breakfast if you aren't hungry.  Pretty much everything you've been told about breakfast as a child is a lie – unless your'e actually hungry, eating an obligatory breakfast in the morning is going to lower your energy(and your testosterone if you are a guy) and make you hungrier later in the day.  Simply stick to eating when you're hungry.
  - Cheese is good in a limited fashion.  If you aren't consuming other carbs throughout the day, even 8 oz of cheese isn't going to knock you out of ketosis by any means.
  - No matter what, you're going to be lower on energy than if you were on a common diet.  You'll get used to it, but I never have any of those moments at the gym where I'm in the zone.  It's just a fact of the body having to create its own glucose.
  - If you don't work out in the morning, try switching your workout routine to happen in the morning.  Supposedly your testosterone will be at its highest which helps with otherwise sluggishness when you're working out.
  - Variety.  Variety.  Variety.  Eating the same thing day in and day out, even if it's fairly tasty and convenient, is the road to the end of a ketogenic diet.  Eat a lot of eggs?  Cook them differently than you usually do, just for the sake of it.  Prepare things in different ways to keep things interesting.
  - Electrolytes.
  - Don't go overboard on protein.  I know that's basics, but I tend to forget that a lot.
  - Don't go overboard on nuts.  I rarely have nuts, but I'll sometimes add brazil nuts to my diet because I don't have any noticeable gastric effects and there's a lot of good fats and minerals in them.
  - Ketone sticks are great to keep you motivated, kind of like a scale when you're focused on losing weight, but don't take the color level too seriously.  If you have more than just trace amounts of ketones, you're in ketosis.