1. Clean and check the connections at the Battery terminals, Solenoid, Starter switch, and Starter. Check feed wires for fraying, cuts or evidence of damage.
2. With Clean terminals, Load test the Battery: Available for free at most Pep Boys / Auto Zone Stores if you don't have a Test Box.
IF the battery tests good, It gets a bit more complicated from there.
1. Does the starter get very hot when cranking? Indicates an excessive load, low current and a possibly bad starter.
2. When is the last time you replaced your spark plug? Gap erosion will cause hard starting. Switch to an irridium plug. Check boot, wire and coil accordingly
3. Fuel quality and pressure, replace gas with fresh stuff and clean the fuel filter if there is one on yours. LTR's are notorious for this, I keep 4 Suzuki fuel filters in stock at all times. Today's gas blends, especially near Chicago, DC, D-FW, NYC and Cali can go bad in just few weeks due to the sh*tty fuel blends they use to reduce smog.
IF the simple stuff doesn't remedy it:
1. Check valve lash tolerances. Tight valves will mimic the symptoms you speak of.
2. Modified motors will start hard if the fuel curves are not properly set. Is your motor a mod motor? Even slightly?
3. Check Compression. Compression on a warm motor will be higher due to the heat swelling of the piston and the sealing action of the oil film on the rings. Low compression will cause hard cold starting.